0001564590-22-007618 | 10-K | XBRL Viewer | Heron Therapeutics INC DE

Summary of Stock Option Plan Activity

The following table summarizes the stock option plan activity:

	Outstanding Options
				Weighted-
				Average
	Number of			Exercise
	Shares			Price
Balance at December 31, 2020		18,912,529		$	19.59
Granted		2,053,980		$	12.39
Exercised		(369,978	)	$	15.29
Cancelled		(1,652,594	)	$	21.69
Balance at December 31, 2021		18,943,937		$	18.71



	Outstanding RSUs
				Weighted-
				Average
	Number of			Grant Date
	Shares			Fair Value
Balance at December 31, 2020		602,741		$	15.84
Granted		2,448,957		$	10.86
Released		(154,487	)	$	15.98
Forfeited		(94,018	)	$	15.07
Balance at December 31, 2021		2,803,193		$	11.51

Schedule of Options Exercisable, Vested or Expected to Vest

	Years Ended December 31,
	2021				2020				2019
			Weighted-				Weighted-				Weighted-
			Average				Average				Average
			Exercise				Exercise				Exercise
	Options		Price		Options		Price		Options		Price
Exercisable at end of year		12,243,887	$	19.13		10,237,202	$	18.74		7,436,379	$	17.02
Options vested or expected to vest		18,416,243	$	18.77		18,179,553	$	19.58		15,962,432	$	20.31

Schedule of Exercise Prices And Weighted-average Remaining Contractual Lives For Options Outstanding

Exercise prices and weighted-average remaining contractual lives for the options outstanding as of December 31, 2021 were:

									Weighted-
			Weighted-						Average
			Average		Weighted-				Exercise
			Remaining		Average				Price of
Outstanding		Range of	Contractual		Exercise		Options		Options
Options		Exercise Prices	Life (in years)		Price		Exercisable		Exercisable
	2,697,794	$7.20–$10.55		5.28	$	9.09		1,598,055	$	8.17
	2,266,285	$10.64–$15.15		5.84		13.40		1,663,593		13.39
	3,307,235	$15.22-$15.72		8.54		15.71		1,035,174		15.70
	2,824,254	$15.75–$18.18		5.73		16.94		2,518,197		16.91
	3,045,374	$18.26–$24.97		6.56		23.04		2,276,351		23.17
	3,102,637	$25.02		7.76		25.02		1,619,032		25.02
	1,700,358	$25.06–$39.00		5.23		30.53		1,533,485		30.52
	18,943,937			6.59		18.71		12,243,887		19.13

Summary of Stock-Based Compensation Expense related to Stock-Based Payment Awards

The following table summarizes stock-based compensation expense related to stock-based payment awards pursuant to our equity compensation arrangements (in thousands):

	December 31,
	2021		2020		2019
Research and development	$	19,482	$	20,731	$	19,202
General and administrative		11,816		15,601		13,564
Sales and marketing		15,553		13,886		18,645
Total stock-based compensation expense	$	46,851	$	50,218	$	51,411

Summary of Fair Value of Option Grant and ESPP Purchase Right on Grant Date Using Black-Scholes Option Pricing Model

We estimated the fair value of each option grant and ESPP purchase right on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions:

Options:

	December 31,
	2021			2020			2019
Risk-free interest rate		1.1	%		0.5	%		1.8	%
Dividend yield		—	%		—	%		—	%
Volatility		62.6	%		69.4	%		66.5	%
Expected life (years)		6			6			6

ESPP:

	December 31,
	2021			2020			2019
Risk-free interest rate		0.1	%		0.1	%		1.9	%
Dividend yield		—	%		—	%		—	%
Volatility		46.9	%		67.7	%		52.1	%
Expected life (months)		6			6			6

Equity Incentive Plan - Schedule of Options Exercisable, Vested or Expected to Vest (Details) - $ / shares	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Options exercisable at end of year	12,243,887	10,237,202	7,436,379
Options vested or expected to vest	18,416,243	18,179,553	15,962,432
Options exercisable at end of year, weighted average exercise price	$ 19.13	$ 18.74	$ 17.02
Options vested or expected to vest, weighted average exercise price	$ 18.77	$ 19.58	$ 20.31

Summary of Significant Accounting Policies - Percentage of Net Product Sales and Accounts Receivable Balance (Details) - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2021
Revenue Benchmark \| Largest Customer
Product Information [Line Items]
Concentration risk percentage	44.70%
Revenue Benchmark \| Second Largest Customer
Product Information [Line Items]
Concentration risk percentage	34.90%
Revenue Benchmark \| Third Largest Customer
Product Information [Line Items]
Concentration risk percentage	19.20%
Revenue Benchmark \| Total Customer
Product Information [Line Items]
Concentration risk percentage	98.80%
Accounts Receivable \| Largest Customer
Product Information [Line Items]
Concentration risk percentage	50.20%
Accounts Receivable \| Second Largest Customer
Product Information [Line Items]
Concentration risk percentage	33.80%
Accounts Receivable \| Third Largest Customer
Product Information [Line Items]
Concentration risk percentage	15.30%
Accounts Receivable \| Total Customer
Product Information [Line Items]
Concentration risk percentage	99.30%

Revenue Recognition - Schedule of Disaggregated Net Product Sales (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Product Information [Line Items]
Net product sales	$ 86,346	$ 88,638	$ 145,968
CINVANTI
Product Information [Line Items]
Net product sales	73,507	87,815	132,162
SUSTOL
Product Information [Line Items]
Net product sales	9,915	$ 823	$ 13,806
ZYNRELEF
Product Information [Line Items]
Net product sales	$ 2,924

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Future Minimum Lease Payments

Annual future minimum lease payments as of December 31, 2021 are as follows (in thousands):

Year ended December 31:
2022	$	2,885
2023		2,970
2024		3,030
2025		3,097
2026		—
Thereafter		—
Total future minimum lease payments		11,982
Less: discount		(1,569	)
Total lease liabilities	$	10,413

Balance Sheet Details - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 36,977	$ 33,609
Less: accumulated depreciation and amortization	(13,243)	(10,872)
Property and equipment, net	23,734	22,737
Scientific Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	33,403	29,135
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	610	878
Computer Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,497	1,461
Furniture, Fixtures and Office Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,467	$ 2,135

Balance Sheet Details - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt securities, impairment losses	$ 0	$ 0
Debt securities, available-for-sale, unrealized gain (loss)	(300,000)	200,000	$ 200,000
Debt securities, available-for-sale, realized gain (loss)	0	0	8,000
Inventory	48,382,000	41,905,000
Depreciation and amortization	3,021,000	2,847,000	$ 2,044,000
Construction in Progress, Gross	15,900,000	14,100,000
ZYNRELEF
Inventory	23,600,000
SUSTOL
Inventory	1,700,000	4,100,000
Cost of product sales, charges	3,800,000	100,000
CINVANTI
Inventory	$ 23,100,000	$ 37,800,000

Balance Sheet Details

12 Months Ended

Dec. 31, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Balance Sheet Details

4.	Balance Sheet Details

Short-Term Investments

The following is a summary of our short-term investments (in thousands):

	December 31, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. corporate debt	$	15,009	$	—	$	(3	)	$	15,006
Foreign corporate debt		10,551		—		(3	)		10,548
U.S. commercial paper		5,998		—		—			5,998
Foreign commercial paper		35,487		—		—			35,487
Total	$	67,045	$	—	$	(6	)	$	67,039

	December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. treasury bills and government agency obligations	$	20,110	$	166	$	—	$	20,276
U.S. corporate debt securities		11,505		42		—		11,547
Foreign corporate debt securities		15,508		49		—		15,557
U.S. commercial paper		13,997		—		—		13,997
Foreign commercial paper		41,976		—		—		41,976
Total	$	103,096	$	257	$	—	$	103,353

The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. We regularly monitor and evaluate the realizable value of our marketable securities. We did not recognize any impairment losses for the years ended December 31, 2021 and 2020.

Unrealized gains and losses associated with our investments are reported in accumulated other comprehensive loss. For the year ended December 31, 2021, we recorded $0.3 million in net unrealized losses associated with our short-term investments. For both years ended December 31, 2020 and 2019, we recorded $0.2 million in net unrealized gains associated with our short-term investments.

Realized gains and losses associated with our investments, if any, are reported in the statements of operations and comprehensive loss. We did not recognize any realized gains or losses during the years ended December 31, 2021 and 2020. We recognized $8,000 in realized gains during the year ended December 31, 2019.

Inventory

Inventory consists of the following (in thousands):

	December 31,
	2021		2020
Raw materials	$	21,193	$	18,994
Work in process		20,935		6,847
Finished goods		6,254		16,064
Total inventory	$	48,382	$	41,905

As of December 31, 2021, total inventory included $23.6 million related to ZYNRELEF, $23.1 million related to CINVANTI, and $1.7 million related to SUSTOL. As of December 31, 2020, total inventory included $37.8 million related to CINVANTI and $4.1 million related to SUSTOL. In addition, cost of product sales for the years ended December 31, 2021 and 2020 included charges of $3.8 million and $0.1 million, respectively, resulting from the write-off of short-dated SUSTOL inventory.

Prepaid Expenses and Other Assets

Prepaid expenses and other assets consist of the following (in thousands):

	December 31,
	2021		2020
Prepaid expenses	$	28,048	$	19,461
Prepaid insurance		2,135		2,155
Deposits		254		346
Interest receivable		245		334
Total prepaid expenses and other assets	$	30,682	$	22,296

Property and Equipment

Property and equipment, net consists of the following (in thousands):

	December 31,
	2021			2020
Scientific equipment	$	33,403		$	29,135
Leasehold improvements		610			878
Computer equipment and software		1,497			1,461
Furniture, fixtures and office equipment		1,467			2,135
Property and equipment, gross		36,977			33,609
Less: accumulated depreciation and amortization		(13,243	)		(10,872	)
Property and equipment, net	$	23,734		$	22,737

Depreciation and amortization expense for the years ended December 31, 2021, 2020 and 2019 was $3.0 million, $2.8 million and $2.0 million, respectively. As of December 31, 2021 and 2020, $15.9 million and $14.1 million of property and equipment, respectively, was in process and not depreciated during the respective years.

Accrued Payroll and Employee Liabilities and Other Accrued Liabilities

Accrued payroll and employee liabilities consist of the following (in thousands):

	December 31,
	2021		2020
Accrued employee salaries and benefits	$	1,784	$	1,691
Accrued bonuses		9,439		8,479
Accrued vacation		4,040		3,427
Total accrued payroll and employee liabilities	$	15,263	$	13,597

Other accrued liabilities consist of the following (in thousands):

	December 31,
	2021		2020
Accrued product sales allowances	$	22,560	$	24,571
Accrued consulting and professional fees		2,666		3,450
Accrued accounts payable		70		104
Other accrued liabilities		563		244
Total other accrued liabilities	$	25,859	$	28,369

Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2021	Dec. 31, 2020
Stockholders Equity Note [Abstract]
Stock options outstanding	18,943,937	18,912,529
Restricted stock units outstanding	2,803,000
Stock options available for grant	869,000
Employee Stock Purchase Plan	201,000
Shares of common stock underlying convertible notes outstanding (see Note 8)	9,819,000
Total shares reserved for future issuance	32,636,000

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2018	$ 370,160	$ 782	$ 1,330,186	$ (87)	$ (960,721)
Balance (in shares) at Dec. 31, 2018		78,174
Issuance of common stock in public offerings, net	162,151	$ 99	162,052
Issuance of common stock in public offerings, net (in shares)		9,857
Conversion benefit included in Convertible Notes issued	416		416
Issuance of common stock under Employee Stock Purchase Plan	2,109	$ 1	2,108
Issuance of common stock under Employee Stock Purchase Plan (in shares)		126
Issuance of common stock under equity incentive plan	22,164	$ 20	22,144
Issuance of common stock under equity incentive plan (in shares)		1,983
Issuance of common stock on exercise of warrants	1	$ 1
Issuance of common stock on exercise of warrants (in shares)		132
Issuance of common stock on conversion of notes (in shares)		32
Stock-based compensation expense	51,411		51,411
Net loss	(204,749)				(204,749)
Net unrealized gain (loss) on short-term investments	172			172
Comprehensive loss	(204,577)
Balance at Dec. 31, 2019	403,835	$ 903	1,568,317	85	(1,165,470)
Balance (in shares) at Dec. 31, 2019		90,304
Conversion benefit included in Convertible Notes issued	440		440
Issuance of common stock under Employee Stock Purchase Plan	2,317	$ 2	2,315
Issuance of common stock under Employee Stock Purchase Plan (in shares)		194
Issuance of common stock under equity incentive plan	6,759	$ 5	6,754
Issuance of common stock under equity incentive plan (in shares)		545
Issuance of common stock on exercise of warrants	3	$ 3
Issuance of common stock on exercise of warrants (in shares)		267
Issuance of common stock on conversion of Convertible Notes	26		26
Stock-based compensation expense	50,218		50,218
Net loss	(227,278)				(227,278)
Net unrealized gain (loss) on short-term investments	172			172
Comprehensive loss	(227,106)
Balance at Dec. 31, 2020	236,492	$ 913	1,628,070	257	(1,392,748)
Balance (in shares) at Dec. 31, 2020		91,310
Conversion benefit included in Convertible Notes issued	230		230
Issuance of common stock under Employee Stock Purchase Plan	2,139	$ 2	2,137
Issuance of common stock under Employee Stock Purchase Plan (in shares)		175
Issuance of common stock under equity incentive plan	4,926	$ 5	4,921
Issuance of common stock under equity incentive plan (in shares)		476
Issuance of common stock on exercise of warrants		$ 2	(2)
Issuance of common stock on exercise of warrants (in shares)		195
Issuance of common stock on conversion of Convertible Notes	7,878	$ 98	7,780
Issuance of common stock on conversion of notes (in shares)		9,849
Stock-based compensation expense	46,851		46,851
Net loss	(220,683)				(220,683)
Net unrealized gain (loss) on short-term investments	(263)			(263)
Comprehensive loss	(220,946)
Balance at Dec. 31, 2021	$ 77,570	$ 1,020	$ 1,689,987	$ (6)	$ (1,613,431)
Balance (in shares) at Dec. 31, 2021		102,005

Balance Sheet Details - Summary of Short -Term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	$ 67,045	$ 103,096
Available-for-sale securities, gross unrealized gains		257
Available-for-sale securities, gross unrealized losses	(6)
Available-for-sale securities	67,039	103,353
U.S. Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	15,009	11,505
Available-for-sale securities, gross unrealized gains		42
Available-for-sale securities, gross unrealized losses	(3)
Available-for-sale securities	15,006	11,547
Foreign Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	10,551	15,508
Available-for-sale securities, gross unrealized gains		49
Available-for-sale securities, gross unrealized losses	(3)
Available-for-sale securities	10,548	15,557
U.S. Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	5,998	13,997
Available-for-sale securities	5,998	13,997
Foreign Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	35,487	41,976
Available-for-sale securities	$ 35,487	41,976
U.S. Treasury Bills and Government Agency Obligations
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost		20,110
Available-for-sale securities, gross unrealized gains		166
Available-for-sale securities		$ 20,276

Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Tax at statutory federal rate	$ (46,343)	$ (47,728)	$ (42,997)
State tax, net of federal benefit	(8,683)	(8,218)	(9,823)
Research and development credits	(4,173)	(4,327)	(4,855)
Stock-based compensation expense	4,584	4,675	2,906
Non-deductible compensation	1,970	1,455	4,720
Change in valuation allowance	51,459	53,621	49,479
Other	1,186	522	570
Provision for income taxes	$ 0	$ 0	$ 0

Schedule of Components of Income Tax Expense (Benefit)

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

The difference between the provision for income taxes and income taxes computed using the effective U.S. federal statutory rate is as follows (in thousands):

	December 31,
	2021			2020			2019
Tax at statutory federal rate	$	(46,343	)	$	(47,728	)	$	(42,997	)
State tax, net of federal benefit		(8,683	)		(8,218	)		(9,823	)
Research and development credits		(4,173	)		(4,327	)		(4,855	)
Stock-based compensation expense		4,584			4,675			2,906
Non-deductible compensation		1,970			1,455			4,720
Change in valuation allowance		51,459			53,621			49,479
Other		1,186			522			570
Provision for income taxes	$	—		$	—		$	—

Schedule of Deferred Tax Assets and Liabilities

Deferred income tax assets and liabilities arising from differences between accounting for financial statement purposes and tax purposes, less valuation allowance at year-end are as follows (in thousands):

	December 31,
	2021			2020
Deferred tax assets:
Net operating loss carryforward	$	294,189		$	251,971
Research and development credits		55,789			49,683
Stock-based compensation		23,342			20,211
Lease liabilities		2,564			4,330
Other		3,953			3,777
Total gross deferred tax assets		379,837			329,972
Deferred tax liabilities:
Right-of-use lease assets		(2,420	)		(4,014	)
Total gross deferred tax liabilities		(2,420	)		(4,014	)
Valuation allowance		(377,417	)		(325,958	)
Net deferred tax assets	$	—		$	—

Summary of Unrecognized Tax Benefits

A reconciliation of our unrecognized tax benefits is as follows (in thousands):

	Year Ended December 31,
	2021		2020		2019
Balance at beginning of year	$	7,406	$	4,784	$	2,385
Additions for tax positions of prior years		107		341		147
Additions based on tax positions related to current year		2,118		2,281		2,252
Balance at end of year	$	9,631	$	7,406	$	4,784

Revenue Recognition (Tables)

12 Months Ended

Dec. 31, 2021

Revenue From Contract With Customer [Abstract]

Schedule of Disaggregated Net Product Sales

The following table provides disaggregated net product sales (in thousands):

	For the Years Ended December 31,
	2021		2020		2019
CINVANTI net product sales	$	73,507	$	87,815	$	132,162
SUSTOL net product sales		9,915		823		13,806
ZYNRELEF net product sales		2,924		—		—
Total net product sales	$	86,346	$	88,638	$	145,968

Summary of Activity to Product Returns, Distributor Fees and Discounts, Rebates and Administrative Fees

The following table provides a summary of activity with respect to our product returns, distributor fees and discounts, rebates and administrative fees, which are included in other accrued liabilities on the consolidated balance sheets (in thousands):

							Discounts,
							Rebates and
	Product			Distributor			Administrative
	Returns			Fees			Fees			Total
Balance at December 31, 2020	$	2,704		$	3,930		$	17,937		$	24,571
Provision		364			18,046			141,262			159,672
Payments/credits		(489	)		(18,510	)		(142,684	)		(161,683	)
Balance at December 31, 2021	$	2,579		$	3,466		$	16,515		$	22,560

Reorganization - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Restructuring charges, total	$ 1.6	$ 5.6		$ 5.6
Research and Development Expense
Restructuring charges, total				1.2
General and Administrative Expense
Restructuring charges, total				3.7
Sales and Marketing Expense
Restructuring charges, total				$ 0.7
Employee Severance
Restructuring charges, total	1.5	2.5
Accelerated Non-Cash Stock Option Expense
Restructuring charges, total	$ 0.1	$ 3.1
2021 Restructuring Plan \| Employee Severance
Payments for restructuring charges			$ 1.3
2020 Restructuring Plan \| Employee Severance
Payments for restructuring charges			$ 2.5

Balance Sheet Details - Schedule of Prepaid Expenses and Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Prepaid Expense And Other Assets Current [Abstract]
Prepaid expenses	$ 28,048	$ 19,461
Prepaid insurance	2,135	2,155
Deposits	254	346
Interest receivable	245	334
Total prepaid expenses and other assets	$ 30,682	$ 22,296

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of Heron Therapeutics, Inc. and its wholly-owned subsidiary, Heron Therapeutics B.V., which was organized in the Netherlands in March 2015. Heron Therapeutics B.V. has no operations and no material assets or liabilities, and there have been no significant transactions related to Heron Therapeutics B.V. since its inception.

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the U.S. (“GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and disclosures made in the accompanying notes to the financial statements. Our significant accounting policies that involve significant judgment and estimates include revenue recognition, investments, inventory and the related reserves, accrued clinical liabilities, income taxes and stock-based compensation. Actual results could differ materially from those estimates.

Cash, Cash Equivalents and Short-term Investments

Cash and cash equivalents consist of cash and highly liquid investments with contractual maturities of three months or less from the original purchase date.

Short-term investments consist of securities with contractual maturities of greater than three months from the original purchase date. Securities with contractual maturities greater than one year are classified as short-term investments on the consolidated balance sheets, as we have the ability, if necessary, to liquidate these securities to meet our liquidity needs in the next 12 months. We have classified our short-term investments as available-for-sale securities in the accompanying consolidated financial statements. Available-for-sale securities are stated at fair market value, with net changes in unrealized gains and losses reported in other comprehensive loss and realized gains and losses included in other income (expense), net. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income.

Fair Value of Financial Instruments

Financial instruments, including cash and cash equivalents, receivables, inventory, prepaid expenses, other current assets, accounts payable and accrued expenses, are carried at cost, which is considered to be representative of their respective fair values because of the short-term maturity of these instruments. Short-term available-for-sale investments are carried at fair value (see Note 3). Our convertible notes outstanding at December 31, 2021 do not have a readily available ascertainable market value, however, the carrying value is considered to approximate its fair value.

Concentration of Credit Risk

Cash, cash equivalents and short-term investments are financial instruments that potentially subject us to concentrations of credit risk. We deposit our cash in financial institutions. At times, such deposits may be in excess of insured limits. We may also invest our excess cash in money market funds, U.S. government and agencies, corporate debt securities and commercial paper. We have established guidelines relative to our diversification of our cash investments and their maturities in an effort to maintain safety and liquidity. These guidelines are periodically reviewed and modified to take advantage of trends in yields and interest rates.

CINVANTI, SUSTOL and ZYNRELEF (collectively, our “Products”) are distributed in the U.S. through a limited number of specialty distributors and full line wholesalers (collectively, “Customers”) that resell to healthcare providers and hospitals, the end users of our Products.

The following table includes the percentage of net product sales and accounts receivable balances for our three major Customers, each of which comprised 10% or more of our net product sales:

	Net Product Sales			Accounts Receivable
	Year Ended December 31, 2021			As of December 31, 2021
Customer A		44.7	%		50.2	%
Customer B		34.9	%		33.8	%
Customer C		19.2	%		15.3	%
Total		98.8	%		99.3	%

Accounts Receivable, Net

Accounts receivable are recorded at the invoice amount, net of an allowance for credit losses. The allowance for credit losses reflects accounts receivable balances that are believed to be uncollectible. In estimating the allowance for credit losses, we consider: (1) our historical experience with collections and write-offs; (2) the credit quality of our Customers and any recent or anticipated changes thereto; (3) the outstanding balances and past due amounts from our Customers; and (4) reasonable and supportable forecast of economic conditions expected to exist throughout the contractual term of the receivable.

We offered extended payment terms to our Customers in connection with our product launches of CINVANTI and ZYNRELEF in January 2018 and July 2021, respectively. In addition, we offered extended payment terms to our Customers in January 2021 when we reinstated the promotion and contracting of SUSTOL. These extended payment terms were offered in anticipation of the timing of reimbursement by government and commercial payers. Effective January 2019, we shortened payment terms to our CINVANTI Customers. As of December 31, 2021, extended payment terms given to our Customers were evaluated in accordance with GAAP and did not impact the collectability of accounts receivables.

As of December 31, 2021 and 2020, we determined that an allowance for doubtful accounts was not required. For the years ended December 31, 2021 and 2020, we did not write-off any accounts receivable balances.

Inventory

Inventory is stated at the lower of cost or estimated net realizable value on a first-in, first-out, or FIFO, basis. We periodically analyze our inventory levels and write down inventory that has become obsolete, inventory that has a cost basis in excess of its estimated realizable value and inventory quantities that are in excess of expected sales requirements as cost of product sales. The determination of whether inventory costs will be realizable requires estimates by management. If actual market conditions are less favorable than projected by management, additional write-downs of inventory may be required, which would be recorded as cost of product sales.

Property and Equipment

Property and equipment is stated at cost less accumulated depreciation and amortization. Depreciation is calculated on a straight-line basis over the estimated useful lives of the assets (generally 5 years). Leasehold improvements are stated at cost and amortized on a straight-line basis over the shorter of the estimated useful life of the asset or the lease term.

Impairment of Long-Lived Assets

If indicators of impairment exist, we assess the recoverability of the affected long-lived assets by determining whether the carrying value of such assets can be recovered through undiscounted future operating cash flows. If impairment is indicated, we measure the amount of such impairment by comparing the carrying value of the asset to the fair value of the asset and record the impairment as a reduction in the carrying value of the related asset with a corresponding charge to operating expenses. Estimating the undiscounted future operating cash flows associated with long-lived assets requires judgment and assumptions that could differ materially from actual results.

Leases

We determine if an arrangement is a lease or contains lease components at inception. Operating leases with an initial term greater than 12 months are recorded as lease liabilities with corresponding right-of-use (“ROU”) lease assets on the consolidated balance sheets. ROU lease assets represent our right to use the underlying assets over the lease term, and lease liabilities represent the present value of our obligation to make lease payments arising from the lease. Lease liabilities are recognized at the lease commencement based on the present value of lease payments over the lease term. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. We use the implicit rate when readily determinable. The ROU lease assets equal the lease liabilities, less unamortized lease incentives, unamortized initial direct costs and the cumulative difference between rent expense and amounts paid under the lease. The lease term includes any option to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense is recognized on a straight-line basis over the lease term. We have lease agreements with both lease and non-lease components, which are generally accounted for separately.

Revenue Recognition

Revenue is recognized in accordance with the Financial Accounting Standards Board (the “FASB”) Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers (“Topic 606”). Topic 606 is based on the principle that revenue should be recognized to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services.

Product Sales

Our Products are distributed in the U.S. through a limited number of Customers that resell to healthcare providers and hospitals, the end users of our Products.

Revenue is recognized in an amount that reflects the consideration we expect to receive in exchange for our Products. To determine revenue recognition for contracts with customers within the scope of Topic 606, we perform the following 5 steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations of the contract(s); (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract(s); and (v) recognize revenue when (or as) we satisfy the performance obligations.

Product Sales Allowances

We recognize product sales allowances as a reduction of product sales in the same period the related revenue is recognized. Product sales allowances are based on amounts owed or to be claimed on the related sales. These estimates take into consideration the terms of our agreements with Customers, historical product returns, rebates or discounts taken, the shelf life of the product and specific known market events, such as competitive pricing and new product introductions. If actual future results vary from our estimates, we may need to adjust these estimates, which could have an effect on product sales and earnings in the period of adjustment. Our product sales allowances include:

•

Product Returns—We allow our Customers to return product for credit for up to 12 months after its product expiration date. As such, there may be a significant period of time between the time the product is shipped and the time the credit is issued on returned product.

•

Distributor Fees—We offer contractually determined discounts to our Customers. These discounts are paid no later than two months after the quarter in which product was shipped.

•

Group Purchasing Organization (“GPO”) Discounts and Rebates—We offer cash discounts to GPO members. These discounts are taken when the GPO members purchase product from our Customers, who then charge back to us the discount amount. Additionally, we offer volume and contract-tier rebates to GPO members. Rebates are based on actual purchase levels during the quarterly rebate purchase period.

•

GPO Administrative Fees—We pay administrative fees to GPOs for services and access to data. These fees are based on contracted terms and are paid after the quarter in which the product was purchased by the GPOs’ members.

•

Medicaid Rebates—We participate in Medicaid rebate programs, which provide assistance to certain low-income patients based on each individual state’s guidelines regarding eligibility and services. Under the Medicaid rebate programs, we pay a rebate to each participating state, generally within three months after the quarter in which the product was sold.

We believe our estimated allowance for product returns requires a high degree of judgment and is subject to change based on our experience and certain quantitative and qualitative factors. We believe our estimated allowances for distributor fees, GPO discounts, rebates and administrative fees and Medicaid rebates do not require a high degree of judgment because the amounts are settled within a relatively short period of time.

Our product sales allowances and related accruals are evaluated each reporting period and adjusted when trends or significant events indicate that a change in estimate is appropriate. Changes in product sales allowance estimates could materially affect our results of operations and financial position.

Accrued Clinical Liabilities

We accrue clinical costs based on work performed, which relies on estimates of the progress of the trials and the related expenses incurred. Clinical trial related contracts vary significantly in duration, and may be for a fixed amount, based on the achievement of certain contingent events or deliverables, a variable amount based on actual costs incurred, capped at a certain limit or contain a combination of these elements. Revisions are recorded to research and development expense in the period in which the facts that give rise to the revision become known. Historically, revisions have not resulted in material changes to research and development expense; however, a modification in the protocol of a clinical trial or cancellation of a clinical trial could result in a material charge to our results of operations.

Research and Development Expense

All costs of research and development are expensed in the period incurred. Research and development expense primarily consists of personnel and related costs, stock-based compensation expense, fees paid to outside service providers and consultants, facilities costs and materials used in clinical and preclinical trials and research and development.

Patent Costs

We incur outside legal fees in connection with filing and maintaining our various patent applications. All patent costs are expensed as incurred and are included in general and administrative expense in the consolidated statements of operations and comprehensive loss.

Stock-Based Compensation Expense

We estimate the fair value of stock-based payment awards using the Black-Scholes option pricing model. This fair value is then amortized using the straight-line single-option method of attributing the value of stock-based compensation to expense over the requisite service periods of the awards. The Black-Scholes option pricing model requires the input of complex and subjective assumptions, including each option’s expected life and price volatility of the underlying stock.

As stock-based compensation expense is based on awards ultimately expected to vest, it has been reduced for estimated forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Forfeitures are estimated based on historical data.

Warrants

We have issued warrants to purchase shares of our common stock in conjunction with certain equity financings or in exchange for services. The terms of the warrants were evaluated to determine the appropriate classification as equity or a liability.

Income Taxes

We recognize the impact of a tax position in our consolidated financial statements if the position is more likely than not to be sustained on examination and on the technical merits of the position. The total amount of unrecognized tax benefits, if recognized, would affect other tax accounts, primarily deferred taxes in future periods, and would not affect our effective tax rate, since we maintain a full valuation allowance against our deferred tax assets (see Note 10). We recognize interest and penalties related to income tax matters in income tax expense.

Comprehensive Loss

Comprehensive loss is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources. Net changes in unrealized gains and losses on available-for-sale securities are included in other comprehensive income (loss) and represent the difference between our net loss and comprehensive net loss for all periods presented.

Net Loss per Share

Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration of common stock equivalents. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, stock options, warrants and shares of common stock underlying Convertible Notes are considered to be common stock equivalents and are included in the calculation of diluted net loss per share only when their effect is dilutive.

Because we have incurred a net loss for all periods presented in the consolidated statements of operations and comprehensive loss, the following common stock equivalents were not included in the computation of net loss per share because their effect would be anti-dilutive (in thousands):

	December 31,
	2021		2020		2019
Stock options outstanding		18,944		18,912		16,665
Restricted stock units outstanding		2,803		603		—
Warrants outstanding		—		220		508
Shares of common stock underlying convertible notes outstanding		9,819		9,510		8,960

Recent Accounting Pronouncements

Adopted in 2021

In December 2019, the FASB issued Accounting Standards Update (“ASU”) No. 2019-12, Income Taxes (Topic 740) (“ASU 2019-12”), which is intended to simplify the accounting for income taxes by eliminating certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. ASU 2019-12 also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates. Adoption of ASU 2019-12 requires certain changes to be made prospectively and other changes to be made retrospectively. In the first quarter of 2021, we adopted the provisions of ASU 2019-12, which did not have a material impact on our results of operations, cash flows, financial condition, internal controls or related disclosures.

Adopted in 2022

In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”). ASU 2020-06 simplifies the accounting for convertible instruments primarily by eliminating the existing cash conversion and beneficial conversion models within Subtopic 470-20, which will result in fewer embedded conversion options being accounted for separately from the debt host. ASU 2020-06 also amends and simplifies the calculation of earnings per share relating to convertible instruments. ASU 2020-06 is effective for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. The provisions of ASU 2020-06 allow for either a modified retrospective or a full retrospective adoption approach. In the first quarter of 2022, we adopted the provisions of ASU 2020-06 using the modified retrospective approach, which did not have a material impact on our results of operations, cash flows, financial condition and related disclosures.

Fair Value Measurements

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements

3.	Fair Value Measurements

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The FASB ASC Topic 820, Fair Value Measurements & Disclosures, establishes a fair value hierarchy which prioritizes the inputs used in measuring fair value as follows:

•

Level 1—Observable inputs such as quoted prices in active markets for identical assets or liabilities.

•

Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

•

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

We measure cash, cash equivalents and short-term investments at fair value on a recurring basis. The fair values of these such assets were as follows (in thousands):

	Fair Value Measurements at Reporting Date Using
	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and money market funds	$	86,043	$	86,043	$	—	$	—
U.S. corporate debt securities		15,006		—		15,006		—
Foreign corporate debt securities		10,548		—		10,548		—
U.S. commercial paper		10,496		—		10,496		—
Foreign commercial paper		35,487		—		35,487		—
Total	$	157,580	$	86,043	$	71,537	$	—

	Fair Value Measurements at Reporting Date Using
	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and money market funds	$	49,149	$	49,149	$	—	$	—
U.S. treasury bills and government agency obligations		20,276		20,276		—		—
U.S. corporate debt securities		11,547		—		11,547		—
Foreign corporate debt securities		15,557		—		15,557		—
U.S. commercial paper		27,996		—		27,996		—
Foreign commercial paper		83,966		—		83,966		—
Total	$	208,491	$	69,425	$	139,066	$	—

We have not transferred any investment securities between the three levels of the fair value hierarchy.

As of December 31, 2021, cash equivalents included $4.5 million of available-for-sale securities with contractual maturities of three months or less and short-term investments included $67.0 million of available-for-sale securities with contractual maturities of three months to one year. As of December 31, 2020, cash equivalents included $55.9 million of available-for-sale securities with contractual maturities of three months or less and short-term investments included $103.4 million of available-for-sale securities with contractual maturities of three months to one year. The money market funds as of December 31, 2021 and 2020 are included in cash and cash equivalents on the consolidated balance sheets.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Common Stock Reserved for Future Issuance

Shares of our common stock reserved for future issuance as of December 31, 2021 were as follows:

	Number of
	Shares
Stock options outstanding		18,944
Restricted stock units outstanding		2,803
Stock options available for grant		869
Employee Stock Purchase Plan		201
Shares of common stock underlying convertible notes outstanding (see Note 8)		9,819
Total shares reserved for future issuance		32,636

Equity Incentive Plan - Summary of Fair Value of Option Grant and ESPP Purchase Right on Grant Date Using Black-Scholes Option Pricing Model (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Payment Arrangement, Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	1.10%	0.50%	1.80%
Dividend yield	0.00%	0.00%	0.00%
Volatility	62.60%	69.40%	66.50%
Expected life	6 years	6 years	6 years
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	0.10%	0.10%	1.90%
Dividend yield	0.00%	0.00%	0.00%
Volatility	46.90%	67.70%	52.10%
Expected life	6 months	6 months	6 months

Summary of Significant Accounting Policies - Common Stock Equivalents Excluded From Computation of Net Loss Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Payment Arrangement, Option
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded (in shares)	18,944	18,912	16,665
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded (in shares)	2,803	603
Warrant
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded (in shares)		220	508
Convertible Debt Securities
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded (in shares)	9,819	9,510	8,960

Equity Incentive Plans - Summary of Stock Option Plan Activity (Details)	12 Months Ended
	Dec. 31, 2021 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares outstanding \| shares	18,912,529
Number of shares granted \| shares	2,053,980
Number of shares exercised \| shares	(369,978)
Number of shares cancelled \| shares	(1,652,594)
Number of shares outstanding \| shares	18,943,937
Number of shares outstanding, weighted average exercise price \| $ / shares	$ 19.59
Number of shares granted, weighted average exercise price \| $ / shares	12.39
Number of shares exercised, weighted average exercise price \| $ / shares	15.29
Number of shares cancelled, weighted average exercise price \| $ / shares	21.69
Number of shares outstanding, weighted average exercise price \| $ / shares	$ 18.71
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares outstanding \| shares	602,741
Number of shares granted \| shares	2,448,957
Number of shares released \| shares	(154,487)
Number of shares forfeited \| shares	(94,018)
Number of shares outstanding \| shares	2,803,193
Number of shares outstanding, weighted average grant date fair value \| $ / shares	$ 15.84
Number of shares granted, weighted average grant date fair value \| $ / shares	10.86
Number of shares released, weighted average grant date fair value \| $ / shares	15.98
Number of shares forfeited, weighted average grant date fair value \| $ / shares	15.07
Number of shares outstanding, weighted average grant date fair value \| $ / shares	$ 11.51

Secured Notes to Related Party

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

Secured Notes to Related Party

8.	Secured Notes to Related Party

Senior Unsecured Convertible Notes

In May 2021, we entered into a note purchase agreement with funds affiliated with Baker Bros. Advisors LP for a private placement of $150.0 million in Senior Unsecured Convertible Notes (“Notes”). We received a total of $149.0 million, net of issuance costs, from the issuance of these Notes.

The Notes were issued at par. The Notes bear interest at a rate of 1.5% per annum, payable in cash semi-annually in arrears on June 15^th and December 15^th of each year, beginning on December 15, 2021. The Notes mature on May 26, 2026, unless earlier converted, redeemed or repurchased.

The Notes will be subject to redemption at our option, between May 24, 2024 and May 24, 2025, but only if the last reported sale price per share of our common stock exceeds 250% of the conversion price for a specified period of time, or on or after May 24, 2025 if the last reported sale price per share of our common stock exceeds 200% of the conversion price for a specified period of time. The redemption price will be equal to the principal amount of the Notes to be redeemed, plus accrued and unpaid interest.

Upon conversion, we will settle the Notes in shares of our common stock. The initial conversion rate for the Notes is 65.4620 shares per $1,000 principal amount of the Notes (equivalent to an initial conversion price of $15.276 per share of common stock).

If a holder of the Notes converts upon a make-whole fundamental change or company redemption, the holder may be eligible to receive a make-whole premium through an increase to the conversion rate.

In May 2021, we filed a registration statement with the SEC to register for resale 12.4 million shares of our common stock underlying the Notes, including the maximum number of shares of common stock issuable under the make-whole premium.

The Notes were accounted for in accordance with ASC Subtopic 470-20, Debt with Conversion and Other Options (“ASC 470-20”) and ASC Subtopic 815-40, Contracts in Entity’s Own Equity (“ASC 815-40”). Under ASC 815-40, to qualify for equity classification (or non-bifurcation, if embedded), the instrument (or embedded feature) must be both (1) indexed to the issuer’s stock and (2) meet the requirements of the equity classification guidance. Based upon our analysis, it was determined that the Notes do contain embedded features indexed to our own stock, but do not meet the requirements for bifurcation, and therefore do not need to be separately accounted for as an equity component. Since the embedded conversion feature meets the equity scope exception from derivative accounting, and, also since the embedded conversion option does not need to be separately accounted for as an equity component under ASC 470-20, the proceeds received from the issuance of the Notes were recorded as a liability on the consolidated balance sheets.

We incurred issuance costs related to the Notes of $1.0 million, which we recorded as debt issuance costs and are included as a reduction to the Notes on the consolidated balance sheets. The debt issuance costs are being amortized to interest expense using the effective interest rate method over the term of the Notes, resulting in an effective interest rate of 1.6%. For the year ended December 31, 2021, interest expense related to the Notes was $1.4 million, which included $1.3 million related to the stated interest rate and $0.1 million related to the amortization of debt issuance costs. As of December 31, 2021, the carrying value of the Notes was $149.1 million, which is comprised of the $150.0 million principal amount of the Notes outstanding, less debt issuance costs of $0.9 million.

Convertible Notes

In April 2011, we entered into a securities purchase agreement for a private placement of up to $4.5 million in Senior Secured Convertible Notes (“Convertible Notes”) with certain investors, including Tang Capital Partners, LP (“TCP”). TCP is controlled by Tang Capital Management, LLC (“TCM”). The manager of TCM is Kevin Tang, who served as a director at the time. At the time of issuance, the terms of the Convertible Notes were determined by our independent directors to be no less favorable than terms that would be obtained in an arm’s length financing transaction. We received a total of $4.3 million, net of issuance costs, from the issuance of these Convertible Notes.

The Convertible Notes were secured by substantially all of our assets, including placing our bank and investment accounts under a control agreement. The Convertible Notes bore interest at 6% per annum, payable quarterly in cash or in additional principal amount of Convertible Notes, at the election of the purchasers. The Convertible Notes matured on May 2, 2021.

In 2011, we filed a registration statement with the SEC to register for resale 3.5 million shares underlying the Convertible Notes. The registration statement was declared effective on July 29, 2011. The Convertible Note holders have agreed to waive their right to require us to maintain the effectiveness of the registration statement.

The Convertible Notes contain an embedded conversion feature that was in-the-money on the issuance dates. Based on an effective fixed conversion rate of 1,250 shares for every $1,000 of principal and accrued interest due under the Convertible Notes, the total conversion benefit at issuance exceeded the loan proceeds. Therefore, a debt discount was recorded in an amount equal to the face value of the Convertible Notes on the issuance dates, and we began amortizing the resultant debt discount over the respective 10-year term of the Convertible Notes. During the year ended December 31, 2021, accrued interest of $0.2 million was paid-in-kind and rolled into the Convertible Note principal balance, which resulted in an additional debt discount of $0.2 million. For the years ended December 31, 2021, 2020 and 2019, interest expense relating to the stated rate was $0.2 million, $0.4 million and $0.4 million, respectively, and interest expense relating to the amortization of the debt discount was $0.8 million, $1.4 million and $1.1 million, respectively.

In May 2021, holders of the Convertible Notes exercised their right to convert the outstanding principal and accrued interest into shares, which resulted in the issuance of 9.8 million shares of common stock. Upon issuance of these shares, there were no remaining obligations under the Convertible Notes.

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

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Compensation And Retirement Disclosure [Abstract]

Employee Benefit Plan

12 Months Ended

Dec. 31, 2021

Employee Benefit Plan

11.	Employee Benefit Plan

We have a defined contribution 401(k) plan (“Plan”) covering substantially all of our employees. In the past three calendar years, we made matching cash contributions equal to 50% of each participant’s contribution during the Plan year up to a maximum amount equal to the lesser of 3% of each participant’s annual compensation or $8,700, $8,550 and $8,400 for the years ended December 31, 2021, 2020 and 2019, respectively. Such amounts were recorded as expense in the corresponding years. We may also contribute additional discretionary amounts to the Plan as we determine. For the years ended December 31, 2021, 2020 and 2019, we contributed $1.3 million, $1.1 million and $1.0 million, respectively, to the Plan. No discretionary contributions have been made to the Plan since its inception.

The entire disclosure for retirement benefits.

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Organization and Business - Additional Information (Details) $ in Thousands	Dec. 31, 2021 USD ($) Country	Dec. 31, 2020 USD ($)
Business [Line Items]
Accumulated deficit	$ 1,613,431	$ 1,392,748
Cash, cash equivalents and short-term investments	$ 157,600
H T X011 \| Europe
Business [Line Items]
Number of countries approved the drug \| Country	31

Commitments And Contingencies Disclosure [Abstract]

The cumulative amount of the reporting entity's undistributed earnings or deficit.

+ References + Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2021

Commitments and Contingencies

6.	Commitments and Contingencies

Leases

During 2021, we had an operating lease for 73,328 square feet of laboratory and office space in San Diego, California. In October 2021, we entered into a lease amendment to reduce the amount of laboratory and office space in San Diego, California by 21,180 square feet. The corresponding reduction of leased space was effective November 1, 2021. In addition, in October 2021, we entered into a sublease agreement to sublet 23,873 square feet of laboratory and office space in San Diego, California, which is anticipated to be delivered to the subtenant on or before May 1, 2022. The sublease agreement expires on December 31, 2025 and is coterminous with the operating lease for the subleased space.

As of December 31, 2021, we had an operating lease for 52,148 square feet of laboratory and office space in San Diego, California, with a lease term that expires on December 31, 2025. As a result of the sublease agreement, our one 5-year option to renew the lease on expiration applies only with respect to our remaining 28,275 square feet of laboratory and office space. During the year ended December 31, 2021, we paid $3.8 million for our operating lease.

We leased 26,067 square feet of laboratory, office and warehouse space in Redwood City, California. The lease for the Redwood City space expired in May 2019. In March 2018, we entered into a sublease agreement for the Redwood City property. The sublease agreement expired in May 2019. We also leased 1,898 square feet of office space in Jersey City, New Jersey. The lease for the Jersey City office space expired in December 2019.

Annual future minimum lease payments as of December 31, 2021 are as follows (in thousands):

Year ended December 31:
2022	$	2,885
2023		2,970
2024		3,030
2025		3,097
2026		—
Thereafter		—
Total future minimum lease payments		11,982
Less: discount		(1,569	)
Total lease liabilities	$	10,413

Rent expense under all operating leases totaled $3.7 million, $3.9 million and $3.1 million for the years ended December 31, 2021, 2020 and 2019, respectively.

Development Agreements

We enter into agreements with clinical sites and clinical research organizations for the conduct of our clinical trials and contract manufacturing organizations for the manufacture and supply of preclinical, clinical and commercial materials and drug product. We make payments to these clinical sites and clinical research organizations based in part on the number of eligible patients enrolled and the length of their participation in the clinical trials. In some of our agreements with contract manufacturing organizations, we are required to meet minimum purchase obligations. Under certain of these agreements, we may be subject to penalties in the event that we prematurely terminate these agreements. At this time, due to the variability associated with clinical site agreements, contract research organization agreements and contract manufacturing agreements, we are unable to estimate with certainty the future costs we will incur. We intend to use our current financial resources to fund our obligations under these commitments.

Purchase Obligations

At December 31, 2021, purchase obligations primarily consisted of non-cancellable commitments with third-party manufacturers in connection with the manufacturing of our commercial products. Total purchase obligations of $98.7 million were not included in our consolidated financial statements for the year ended December 31, 2021 and are due within one to two years.

Reorganization

12 Months Ended

Dec. 31, 2021

Reorganizations [Abstract]

Reorganization

7.	Reorganization

October 2021

In October 2021, we implemented a restructuring plan under which we provided or will provide employees one-time severance payments upon termination, continued benefits for a specific period of time, outplacement services and certain stock option modifications.

The total expense for these activities is $1.6 million, $1.5 million of which is primarily for severance and $0.1 million of which is for non-cash, stock-based compensation expense related to stock option modifications, which was recognized in the fourth quarter of 2021. As of December 31, 2021, we had paid $1.3 million of the total cash severance charges. We have accounted for these expenses in accordance with the FASB ASC Topic 420, Exit or Disposal Cost Obligations.

October 2020

In October 2020, we implemented changes to our organizational structure. In connection with the reorganization, we provided employees one-time severance payments upon termination, continued benefits for a specified period of time, outplacement services and certain stock option modifications.

The total expense for these activities was $5.6 million, $2.5 million of which is primarily for severance and $3.1 million of which is for non-cash, stock-based compensation expense. For the year ended December 31, 2020, total expenses were $5.6 million, with $1.2 million in research and development expense, $3.7 million in general and administrative expense and $0.7 million in sales and marketing expense. As of December 31, 2021, we had paid $2.5 million of the total cash severance charges. We have accounted for these expenses in accordance with the FASB ASC Topic 420, Exit or Disposal Cost Obligations.

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 90,541	$ 105,138
Short-term investments	67,039	103,353
Accounts receivable, net	35,499	41,850
Inventory	48,382	41,905
Prepaid expenses and other current assets	12,962	21,950
Total current assets	254,423	314,196
Property and equipment, net	23,734	22,737
Right-of-use lease assets	9,829	16,277
Other assets	17,720	346
Total assets	305,706	353,556
Current liabilities:
Accounts payable	3,803	525
Accrued clinical and manufacturing liabilities	23,716	49,962
Accrued payroll and employee liabilities	15,263	13,597
Other accrued liabilities	25,859	28,369
Current lease liabilities	2,417	2,997
Convertible notes payable to related parties, net of discount		7,053
Total current liabilities	71,058	102,503
Non-current lease liabilities	7,996	14,561
Non-current convertible notes payable, net	149,082
Total liabilities	228,136	117,064
Commitments and contingencies (see Note 6)
Stockholders’ equity:
Preferred stock, $0.01 par value: 2,500 shares authorized; no shares issued or outstanding at December 31, 2021 and 2020
Common stock, $0.01 par value: 150,000 shares authorized; 102,005 and 91,310 shares issued and outstanding at December 31, 2021 and 2020, respectively	1,020	913
Additional paid-in capital	1,689,987	1,628,070
Accumulated other comprehensive income (loss)	(6)	257
Accumulated deficit	(1,613,431)	(1,392,748)
Total stockholders’ equity	77,570	236,492
Total liabilities and stockholders’ equity	$ 305,706	$ 353,556

Equity Incentive Plan - Summary of Stock-Based Compensation Expense related to Stock-Based Payment Awards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 46,851	$ 50,218	$ 51,411
Research and Development Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	19,482	20,731	19,202
General and Administrative Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	11,816	15,601	13,564
Sales and Marketing Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 15,553	$ 13,886	$ 18,645

Employee Benefit Plan - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match	50.00%	50.00%	50.00%
Defined contribution plan, maximum annual contributions by employer per employee, amount	$ 8,700	$ 8,550	$ 8,400
Defined contribution plan, cost	$ 1,300,000	$ 1,100,000	$ 1,000,000.0
Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of employees' gross pay	3.00%	3.00%	3.00%

Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Dec. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	2,500	2,500
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	150,000	150,000
Common stock, shares issued (in shares)	102,005	91,310
Common stock, shares outstanding (in shares)	102,005	91,310

Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Net product sales	$ 86,346	$ 88,638	$ 145,968
Operating expenses:
Cost of product sales	46,021	36,189	61,619
Research and development	130,821	174,533	167,382
General and administrative	40,153	42,226	37,897
Sales and marketing	87,179	63,853	89,764
Total operating expenses	304,174	316,801	356,662
Loss from operations	(217,828)	(228,163)	(210,694)
Other income (expense), net:
Interest income	433	3,633	7,259
Interest expense	(2,410)	(1,901)	(1,472)
Other income (expense)	(878)	(847)	158
Total other income (expense), net	(2,855)	885	5,945
Net loss	(220,683)	(227,278)	(204,749)
Other comprehensive income (loss):
Unrealized gains (losses) on short-term investments	(263)	172	172
Comprehensive loss	$ (220,946)	$ (227,106)	$ (204,577)
Basic and diluted net loss per share	$ (2.24)	$ (2.50)	$ (2.50)
Shares used in computing basic and diluted net loss per share	98,471	90,774	81,779

Income Taxes

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Income Taxes

12.	Income Taxes

For the years ended December 31, 2021, 2020 and 2019, we did not record a provision for income taxes due to a full valuation allowance against our deferred tax assets.

The difference between the provision for income taxes and income taxes computed using the effective U.S. federal statutory rate is as follows (in thousands):

	December 31,
	2021			2020			2019
Tax at statutory federal rate	$	(46,343	)	$	(47,728	)	$	(42,997	)
State tax, net of federal benefit		(8,683	)		(8,218	)		(9,823	)
Research and development credits		(4,173	)		(4,327	)		(4,855	)
Stock-based compensation expense		4,584			4,675			2,906
Non-deductible compensation		1,970			1,455			4,720
Change in valuation allowance		51,459			53,621			49,479
Other		1,186			522			570
Provision for income taxes	$	—		$	—		$	—

	December 31,
	2021			2020
Deferred tax assets:
Net operating loss carryforward	$	294,189		$	251,971
Research and development credits		55,789			49,683
Stock-based compensation		23,342			20,211
Lease liabilities		2,564			4,330
Other		3,953			3,777
Total gross deferred tax assets		379,837			329,972
Deferred tax liabilities:
Right-of-use lease assets		(2,420	)		(4,014	)
Total gross deferred tax liabilities		(2,420	)		(4,014	)
Valuation allowance		(377,417	)		(325,958	)
Net deferred tax assets	$	—		$	—

We have established a valuation allowance to offset net deferred tax assets as of December 31, 2021 and 2020 due to the uncertainty of realizing future tax benefits from such assets.

As of December 31, 2021, we had federal and state net operating loss (“NOL”) carryforwards of $1.2 billion and $743.4 million, respectively. The federal NOL carryforwards consist of $547.4 million generated before January 1, 2018, which began to expire in 2021, and $664.2 million that can be carried forward indefinitely, but are subject to the 80% taxable income limitation. The state NOL carryforwards will begin to expire in 2028.

As of December 31, 2021, we had federal and state research and development credit carryforwards of $45.3 million and $20.4 million, respectively. The federal research and development credit carryforwards will begin to expire in 2022. The state research and development credit carryforwards will begin to expire in 2023.

Internal Revenue Code (“IRC”) Sections 382 and 383 place a limitation on the amount of taxable income that can be offset by NOL and credit carryforwards after a change in control (generally greater than 50% change in ownership within a three-year period) of a loss corporation. Generally, after a change in control, a loss corporation cannot deduct NOL and credit carryforwards in excess of the IRC Sections 382 and 383 limitation. State jurisdictions have similar rules. We have previously performed an analysis of IRC Sections 382 and 383 through 2018 and determined there were ownership changes in 2007, 2011 and 2013. We are currently in the process of updating our IRC Sections 382 and 383 analysis through 2021. The limitation in the federal and state NOL and research and development credit carryforwards that expire unused would reduce the deferred tax assets, which are fully offset by a valuation allowance.

We file U.S. and state income tax returns with varying statutes of limitations. The tax years from 2001 to 2021 remain open to examination due to the carryover of unused NOL carryforwards and tax credits.

A reconciliation of our unrecognized tax benefits is as follows (in thousands):

	Year Ended December 31,
	2021		2020		2019
Balance at beginning of year	$	7,406	$	4,784	$	2,385
Additions for tax positions of prior years		107		341		147
Additions based on tax positions related to current year		2,118		2,281		2,252
Balance at end of year	$	9,631	$	7,406	$	4,784

Due to our valuation allowance, the $9.6 million of unrecognized tax benefits would not affect the effective tax rate, if recognized. It is the Company’s practice to recognize interest and penalties related to income tax matters in income tax expense. As of December 31, 2021, we had no accrued interest and penalties related to uncertain tax positions. We do not expect any material changes to the estimated amount of liability associated with our uncertain tax positions within the next 12 months.

On March 27, 2020, the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”) was enacted and signed into law in response to the COVID-19 pandemic. GAAP requires recognition of the tax effects of new legislation during the reporting period that includes the enactment date. The CARES Act includes changes to the tax provisions that benefits business entities and makes certain technical corrections to the 2017 Tax Cuts and Jobs Act. The tax relief measures for businesses include a five-year net operating loss carryback, suspension of the annual deduction limitation of 80% of taxable income from net operating losses generated in a tax year beginning after December 31, 2017, changes in the deductibility of interest, acceleration of alternative minimum tax credit refunds, payroll tax relief, technical corrections on net operating loss carryforwards for fiscal year taxpayers and allows accelerated deduction qualified improvement property. The CARES Act also provides other non-tax benefits to assist those impacted by the pandemic. We evaluated the impact of the CARES Act and determined that there was no material impact for the year ended December 31, 2021.

On June 29, 2020, California Assembly Bill 85 was signed into law. The legislation suspends the California net operating loss deductions for 2020, 2021, and 2022 for certain taxpayers and imposes a limitation of certain California tax credits for 2020, 2021, and 2022. The legislation disallows the use of California net operating loss deductions if the taxpayer recognizes business income, and its adjusted gross income is greater than $1.0 million. The carryover periods for net operating loss deductions disallowed by this provision will be extended. Additionally, any business credit will only offset a maximum of $5.0 million of California tax. In 2022, California enacted Senate Bill 113, which removed the net operating loss suspension and limited use of business tax credits for 2022. Senate Bill 113 will have no income tax impact, as we continue to record a full valuation allowance against the deferred tax assets due to our cumulative tax losses.

On December 27, 2020, the “Consolidated Appropriations Act, 2021” was enacted and signed into law to further COVID-19 economic relief and extend certain expiring tax provisions. The relief package includes a tax provision clarifying that businesses with forgiven PPP loans can deduct regular business expenses that are paid for with the loan proceeds. Additional pandemic relief tax measures include an expansion of the employee retention credit, enhanced charitable contribution deductions, and a temporary full deduction for business expenses for food and beverages provided by a restaurant. The provisions did not have a material impact on our financial statements for the year ended December 31, 2021.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

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Percentage of Net Product Sales and Accounts Receivable Balance

Commitments and Contingencies - Additional Information (Details) $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2021 ft²	Dec. 31, 2021 USD ($) ft²	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2021 ft²
Lessee Lease Description [Line Items]
Operating lease, rent expense \| $		$ 3.7	$ 3.9	$ 3.1
Total purchase obligations \| $		$ 98.7
Maximum
Lessee Lease Description [Line Items]
Purchase obligations due period		2 years
Minimum
Lessee Lease Description [Line Items]
Purchase obligations due period		1 year
San Diego, California
Lessee Lease Description [Line Items]
Area of real estate property	21,180	52,148			73,328
Reduction of leased space, effective date	Nov. 01, 2021
Lease expiration date		Dec. 31, 2025
Lessee, operating lease, renewal term		5 years
Remaining area of real estate property	28,275	28,275
Lessee, operating lease, existence of option to extend		true
Operating lease cash payments \| $		$ 3.8
San Diego, California \| Sublease Agreement
Lessee Lease Description [Line Items]
Area of real estate property	23,873
Lease expiration date	Dec. 31, 2025
Redwood City, California
Lessee Lease Description [Line Items]
Area of real estate property		26,067
Lease expiration date		2019-05
Sublease expiration date		2019-05
Jersey City, New Jersey
Lessee Lease Description [Line Items]
Area of real estate property		1,898
Lease expiration date		2019-12

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

The following table includes the percentage of net product sales and accounts receivable balances for our three major Customers, each of which comprised 10% or more of our net product sales:

	Net Product Sales			Accounts Receivable
	Year Ended December 31, 2021			As of December 31, 2021
Customer A		44.7	%		50.2	%
Customer B		34.9	%		33.8	%
Customer C		19.2	%		15.3	%
Total		98.8	%		99.3	%

Common Stock Equivalents Excluded From Computation of Net Loss Per Share

	December 31,
	2021		2020		2019
Stock options outstanding		18,944		18,912		16,665
Restricted stock units outstanding		2,803		603		—
Warrants outstanding		—		220		508
Shares of common stock underlying convertible notes outstanding		9,819		9,510		8,960

Fair Value Measurements - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Financial instruments transferred among fair value hierarchy levels	$ 0
Cash equivalents included of available-for-sale securities	4,500,000	$ 55,900,000
Available for sale securities with contractual maturities of three months to one year.	$ 67,000,000.0	$ 103,400,000

Balance Sheet Details - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued payroll and employee liabilities
Accrued employee salaries and benefits	$ 1,784	$ 1,691
Accrued bonuses	9,439	8,479
Accrued vacation	4,040	3,427
Total accrued payroll and employee liabilities	15,263	13,597
Other accrued liabilities
Accrued product sales allowances	22,560	24,571
Accrued consulting and professional fees	2,666	3,450
Accrued accounts payable	70	104
Other accrued liabilities	563	244
Total other accrued liabilities	$ 25,859	$ 28,369

Commitments and Contingencies - Summary of Future Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Commitments And Contingencies Disclosure [Abstract]
2022	$ 2,885
2023	2,970
2024	3,030
2025	3,097
Total future minimum lease payments	11,982
Less: discount	(1,569)
Total lease liabilities	$ 10,413

Equity Incentive Plan - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended										12 Months Ended
	Jun. 30, 2021	Jun. 30, 2019	Jun. 30, 2017	Jun. 30, 2016	May 31, 2015	May 31, 2014	Jun. 30, 2011	May 31, 2010	May 31, 2009	Dec. 31, 2007	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 1997
Class Of Stock [Line Items]
Share-based compensation arrangements by share-based payment award, options, exercises in period, weighted average exercise price											$ 15.29
Common stock, shares, issued, total											102,005,000	91,310,000
Common stock, capital shares reserved for future issuance											32,636,000
Share-based compensation arrangement by share-based payment award, number of shares available for grant											869,000
Share-based compensation arrangement by share-based payment award, expiration period											10 years
Share-based compensation arrangement by share-based payment award, award vesting period											4 years
Share-based compensation arrangement by share-based payment award, options, exercisable, weighted average remaining contractual term											6 years 7 months 6 days
Share-based compensation arrangement by share-based payment award, options, exercises in period, intrinsic value											$ 0.7	$ 3.2
Share-based compensation arrangement by share-based payment award, options, outstanding, intrinsic value											$ 1.7	$ 69.1
Common stock future issuance on exercise of outstanding options and vesting of outstanding restricted stock units granted											21,747,130
Total unrecognized compensation cost related to non-vested, stock-based payment awards											$ 99.7
Total unrecognized compensation cost, expect to recognize over weighted average period											2 years 9 months 18 days
Restricted Stock Units
Class Of Stock [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period											4 years
Employee Stock Purchase Plan
Class Of Stock [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized														10,000
Share-based compensation arrangement by share-based payment award, number of additional shares authorized	200,000	300,000	200,000	100,000	100,000	25,000	25,000		10,000	5,000	975,000
Share-based compensation arrangement by share-based payment award maximum employee earnings with held to purchase common stock percent											10.00%
Share-based compensation arrangement by share-based payment award discount on stock price											85.00%
Share-based compensation arrangement by share-based payment award, shares issued in period											175,228	193,841	125,727
Share-based compensation arrangements by share-based payment award, options, exercises in period, weighted average exercise price											$ 12.21	$ 11.95	$ 16.77
Common stock, shares, issued, total											773,978
Common stock, capital shares reserved for future issuance											201,022
Share-based compensation arrangement by share-based payment award, options, grants in period, weighted average grant date fair value											$ 7.10	9.76	14.70
Share-based compensation arrangement by share-based payment award, per share weighted-average fair value price of shares purchased											$ 3.64	$ 5.18	$ 5.94
Expected life											6 months
Equity Incentive Plan 2007
Class Of Stock [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized										150,000
Share-based compensation arrangement by share-based payment award, number of additional shares authorized	2,000,000	7,000,000	5,000,000	3,000,000	4,300,000	1,750,000	4,500,000	100,000			27,800,000
Share-based compensation arrangement by share-based payment award, number of shares available for grant											868,880

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis

We measure cash, cash equivalents and short-term investments at fair value on a recurring basis. The fair values of these such assets were as follows (in thousands):

	Fair Value Measurements at Reporting Date Using
	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and money market funds	$	86,043	$	86,043	$	—	$	—
U.S. corporate debt securities		15,006		—		15,006		—
Foreign corporate debt securities		10,548		—		10,548		—
U.S. commercial paper		10,496		—		10,496		—
Foreign commercial paper		35,487		—		35,487		—
Total	$	157,580	$	86,043	$	71,537	$	—

	Fair Value Measurements at Reporting Date Using
	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and money market funds	$	49,149	$	49,149	$	—	$	—
U.S. treasury bills and government agency obligations		20,276		20,276		—		—
U.S. corporate debt securities		11,547		—		11,547		—
Foreign corporate debt securities		15,557		—		15,557		—
U.S. commercial paper		27,996		—		27,996		—
Foreign commercial paper		83,966		—		83,966		—
Total	$	208,491	$	69,425	$	139,066	$	—

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforward	$ 294,189	$ 251,971
Research and development credits	55,789	49,683
Stock-based compensation	23,342	20,211
Lease liabilities	2,564	4,330
Other	3,953	3,777
Total gross deferred tax assets	379,837	329,972
Deferred tax liabilities:
Right-of-use lease assets	(2,420)	(4,014)
Total gross deferred tax liabilities	(2,420)	(4,014)
Valuation allowance	$ (377,417)	$ (325,958)

Balance Sheet Details (Tables)

12 Months Ended

Dec. 31, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Summary of Short-Term Investments

The following is a summary of our short-term investments (in thousands):

	December 31, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. corporate debt	$	15,009	$	—	$	(3	)	$	15,006
Foreign corporate debt		10,551		—		(3	)		10,548
U.S. commercial paper		5,998		—		—			5,998
Foreign commercial paper		35,487		—		—			35,487
Total	$	67,045	$	—	$	(6	)	$	67,039

	December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. treasury bills and government agency obligations	$	20,110	$	166	$	—	$	20,276
U.S. corporate debt securities		11,505		42		—		11,547
Foreign corporate debt securities		15,508		49		—		15,557
U.S. commercial paper		13,997		—		—		13,997
Foreign commercial paper		41,976		—		—		41,976
Total	$	103,096	$	257	$	—	$	103,353

Schedule of Inventory

Inventory consists of the following (in thousands):

	December 31,
	2021		2020
Raw materials	$	21,193	$	18,994
Work in process		20,935		6,847
Finished goods		6,254		16,064
Total inventory	$	48,382	$	41,905

Schedule of Prepaid Expenses and Other Assets

Prepaid expenses and other assets consist of the following (in thousands):

	December 31,
	2021		2020
Prepaid expenses	$	28,048	$	19,461
Prepaid insurance		2,135		2,155
Deposits		254		346
Interest receivable		245		334
Total prepaid expenses and other assets	$	30,682	$	22,296

Schedule of Property and Equipment, Net

Property and equipment, net consists of the following (in thousands):

	December 31,
	2021			2020
Scientific equipment	$	33,403		$	29,135
Leasehold improvements		610			878
Computer equipment and software		1,497			1,461
Furniture, fixtures and office equipment		1,467			2,135
Property and equipment, gross		36,977			33,609
Less: accumulated depreciation and amortization		(13,243	)		(10,872	)
Property and equipment, net	$	23,734		$	22,737

Schedule of Accrued Liabilities

Accrued payroll and employee liabilities consist of the following (in thousands):

	December 31,
	2021		2020
Accrued employee salaries and benefits	$	1,784	$	1,691
Accrued bonuses		9,439		8,479
Accrued vacation		4,040		3,427
Total accrued payroll and employee liabilities	$	15,263	$	13,597

Other accrued liabilities consist of the following (in thousands):

	December 31,
	2021		2020
Accrued product sales allowances	$	22,560	$	24,571
Accrued consulting and professional fees		2,666		3,450
Accrued accounts payable		70		104
Other accrued liabilities		563		244
Total other accrued liabilities	$	25,859	$	28,369

Secured Notes to Related Party - Additional Information (Details) - USD ($)		1 Months Ended		12 Months Ended
	Jul. 29, 2011	May 31, 2021	Apr. 30, 2011	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Net proceeds from convertible notes financing				$ 148,963,000
Amortization of debt issuance costs				119,000
Amortization of debt discount				$ 785,000	$ 1,429,000	$ 1,050,000
Common Stock
Debt Instrument [Line Items]
Initial conversion price/rate		$ 15.276
Issuance of common stock on conversion of notes (in shares)		9,800,000		9,849,000		32,000
Notes
Debt Instrument [Line Items]
Convertible debt issuable in connection with private placement		$ 150,000,000.0
Net proceeds from convertible notes financing		$ 149,000,000.0
Debt instrument, interest rate		1.50%
Debt instrument, maturity date		May 26, 2026
Debt instrument, frequency of periodic payment		semi-annually
Debt instrument, date of first required payment		Dec. 15, 2021
Initial conversion price/rate		$ 65.4620
Debt instrument conversion ratio multiple of principal		$ 1,000
Common shares registered for resale in connection with convertible notes		12,400,000
Debt issuance costs incurred				$ 1,000,000.0
Effective interest rate				1.60%
Interest expense				$ 1,400,000
Interest expense, debt, excluding amortization				1,300,000
Amortization of debt issuance costs				100,000
Carrying value of debt				149,100,000
Debt instrument, face amount				150,000,000.0
Debt issuance costs				900,000
Notes \| Redemption Between May 24, 2024 and May 24, 2025
Debt Instrument [Line Items]
Debt instrument, redemption period, stock price exceeds in percentage of conversion price		250.00%
Notes \| Redemption On or After May 24, 2025
Debt Instrument [Line Items]
Debt instrument, redemption period, stock price exceeds in percentage of conversion price		200.00%
Convertible Notes
Debt Instrument [Line Items]
Convertible debt issuable in connection with private placement			$ 4,500,000
Net proceeds from convertible notes financing			$ 4,300,000
Debt instrument, interest rate			6.00%
Debt instrument, maturity date			May 02, 2021
Debt instrument conversion ratio multiple of principal			$ 1,000
Common shares registered for resale in connection with convertible notes	3,500,000
Interest expense, debt, excluding amortization				200,000	400,000	$ 400,000
Carrying value of debt		$ 0
Debt instrument, term			10 years
Paid-in-kind interest				200,000
Debt instrument, additional debt discount				200,000
Amortization of debt discount				$ 800,000	$ 1,400,000	$ 1,100,000
Convertible Notes \| Common Stock
Debt Instrument [Line Items]
Debt instrument, number of shares issued for convertible notes			1,250

Stockholders' Equity

12 Months Ended

Dec. 31, 2021

Stockholders' Equity

9.	Stockholders’ Equity

2019 Common Stock Offering

In October 2019, we sold 9.9 million shares of our common stock at a public offering price of $17.50 per share. We received total net cash proceeds of $162.2 million (net of $10.3 million in issuance costs) from the sale of the common stock.

Public Offering Warrants

In June 2014, as a component of our public offering, we sold 600,000 pre-funded warrants to purchase shares of our common stock. The pre-funded warrants have an exercise price of $0.01 per share and expire on June 30, 2021. During the year ended December 31, 2019, warrant holders exercised 132,130 warrants, which resulted in the issuance of 132,130 shares for net cash proceeds of $1,321. During the year ended December 31, 2020, warrant holders exercised 267,870 warrants, which resulted in the issuance of 267,870 shares for net cash proceeds of $2,679. In April 2021, warrant holders exercised 195,574 warrants using the cashless exercise provision, which resulted in the issuance of 195,461 shares and no cash proceeds. As of December 31, 2021, no warrants from the June 2014 public offering remain outstanding.

Common Stock Reserved for Future Issuance

Shares of our common stock reserved for future issuance as of December 31, 2021 were as follows:

	Number of
	Shares
Stock options outstanding		18,944
Restricted stock units outstanding		2,803
Stock options available for grant		869
Employee Stock Purchase Plan		201
Shares of common stock underlying convertible notes outstanding (see Note 8)		9,819
Total shares reserved for future issuance		32,636

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

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Revenue Recognition - Summary of Activity to Product Returns, Distributor Fees and Discounts, Rebates and Administrative Fees (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Product Information [Line Items]
Balance	$ 24,571
Provision	159,672
Payments/credits	(161,683)
Balance	22,560
Product Returns
Product Information [Line Items]
Balance	2,704
Provision	364
Payments/credits	(489)
Balance	2,579
Distributor Fees
Product Information [Line Items]
Balance	3,930
Provision	18,046
Payments/credits	(18,510)
Balance	3,466
Discounts, Rebates and Administrative Fees
Product Information [Line Items]
Balance	17,937
Provision	141,262
Payments/credits	(142,684)
Balance	$ 16,515

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2021
Accounting Standards Update 2019-12
Product Information [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, immaterial effect	true
Leasehold Improvements
Product Information [Line Items]
Estimated useful lives	5 years

Indicates (true false) whether accounting standards update was adopted.

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Revenue From Contract With Customer [Abstract]

Balance Sheet Details - Schedule of Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 21,193	$ 18,994
Work in process	20,935	6,847
Finished goods	6,254	16,064
Total inventory	$ 48,382	$ 41,905

Revenue Recognition

12 Months Ended

Dec. 31, 2021

Revenue Recognition

5.	Revenue Recognition

The following table provides disaggregated net product sales (in thousands):

	For the Years Ended December 31,
	2021		2020		2019
CINVANTI net product sales	$	73,507	$	87,815	$	132,162
SUSTOL net product sales		9,915		823		13,806
ZYNRELEF net product sales		2,924		—		—
Total net product sales	$	86,346	$	88,638	$	145,968

							Discounts,
							Rebates and
	Product			Distributor			Administrative
	Returns			Fees			Fees			Total
Balance at December 31, 2020	$	2,704		$	3,930		$	17,937		$	24,571
Provision		364			18,046			141,262			159,672
Payments/credits		(489	)		(18,510	)		(142,684	)		(161,683	)
Balance at December 31, 2021	$	2,579		$	3,466		$	16,515		$	22,560

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

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Summary of Significant Accounting Policies

Fair Value Measurements - Schedule of Financial Assets Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 67,039	$ 103,353
U.S. Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	15,006	11,547
Foreign Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	10,548	15,557
U.S. Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	5,998	13,997
U.S. Treasury Bills and Government Agency Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities		20,276
Fair Value, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	157,580	208,491
Fair Value, Recurring \| Foreign Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	35,487	83,966
Fair Value, Recurring \| U.S. Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	15,006	11,547
Fair Value, Recurring \| Foreign Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	10,548	15,557
Fair Value, Recurring \| U.S. Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	10,496	27,996
Fair Value, Recurring \| U.S. Treasury Bills and Government Agency Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities		20,276
Fair Value, Recurring \| Cash and Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and money market funds	86,043	49,149
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	86,043	69,425
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| U.S. Treasury Bills and Government Agency Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities		20,276
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Cash and Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and money market funds	86,043	49,149
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	71,537	139,066
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| Foreign Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	35,487	83,966
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| U.S. Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	15,006	11,547
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| Foreign Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	10,548	15,557
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| U.S. Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 10,496	$ 27,996

Stockholders' Equity - Additional Information (Details) - USD ($)	1 Months Ended			12 Months Ended
	Apr. 30, 2021	Oct. 31, 2019	Jun. 30, 2014	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Proceeds from issuance of common stock		$ 162,200,000				$ 162,151,000
Share-based Payment Arrangement, Option
Class Of Stock [Line Items]
Share-based compensation arrangement by share-based payment award, options, forfeitures in period				806,244
Share-based compensation arrangements by share-based payment award, options, forfeitures in period, weighted average exercise price				$ 20.51
Share-based compensation arrangement by share-based payment award, options, expirations in period				846,350
Share-based compensation arrangements by share-based payment award, options, expirations in period, weighted average exercise price				$ 22.81
Pre-funded Warrants
Class Of Stock [Line Items]
Class of warrant or right, number of securities called by warrants or rights			600,000
Class of warrant or right, exercise price of warrants or rights			$ 0.01
Class of warrant or right, expiration date			Jun. 30, 2021
Class of warrant or right, exercised during period	195,574				267,870	132,130
Proceeds from issuance of warrants	$ 0				$ 2,679,000	$ 1,321,000
Class of warrant or right, outstanding				0
Common Stock
Class Of Stock [Line Items]
Number of shares issued		9,900,000				9,857,000
Share price		$ 17.50
Payments of stock issuance costs		$ 10,300,000
Issuance of common stock on exercise of warrants (in shares)				195,000	267,000	132,000
Common Stock \| Pre-funded Warrants
Class Of Stock [Line Items]
Issuance of common stock on exercise of warrants (in shares)	195,461				267,870	132,130

Equity Incentive Plan - Schedule of Exercise Prices And Weighted-average Remaining Contractual Lives For Options Outstanding (Details)	12 Months Ended
	Dec. 31, 2021 $ / shares shares
Options Outstanding (in shares) \| shares	18,943,937
Weighted- Average Remaining Contractual Life (Year)	6 years 7 months 2 days
Weighted- Average Exercise Price (in dollars per share)	$ 18.71
Options Exercisable (in shares) \| shares	12,243,887
Weighted- Average Exercise Price of Options Exercisable	$ 19.13
Exercise Price Range 1
Options Outstanding (in shares) \| shares	2,697,794
Range of Exercise Prices, Lower Limit (in dollars per share)	$ 7.20
Range of Exercise Prices, Upper Limit (in dollars per share)	$ 10.55
Weighted- Average Remaining Contractual Life (Year)	5 years 3 months 10 days
Weighted- Average Exercise Price (in dollars per share)	$ 9.09
Options Exercisable (in shares) \| shares	1,598,055
Weighted- Average Exercise Price of Options Exercisable	$ 8.17
Exercise Price Range 2
Options Outstanding (in shares) \| shares	2,266,285
Range of Exercise Prices, Lower Limit (in dollars per share)	$ 10.64
Range of Exercise Prices, Upper Limit (in dollars per share)	$ 15.55
Weighted- Average Remaining Contractual Life (Year)	5 years 10 months 2 days
Weighted- Average Exercise Price (in dollars per share)	$ 13.40
Options Exercisable (in shares) \| shares	1,663,593
Weighted- Average Exercise Price of Options Exercisable	$ 13.39
Exercise Price Range 3
Options Outstanding (in shares) \| shares	3,307,235
Range of Exercise Prices, Lower Limit (in dollars per share)	$ 15.22
Weighted- Average Remaining Contractual Life (Year)	8 years 6 months 14 days
Weighted- Average Exercise Price (in dollars per share)	$ 15.71
Options Exercisable (in shares) \| shares	1,035,174
Weighted- Average Exercise Price of Options Exercisable	$ 15.70
Exercise Price Range 4
Options Outstanding (in shares) \| shares	2,824,254
Range of Exercise Prices, Lower Limit (in dollars per share)	$ 15.75
Range of Exercise Prices, Upper Limit (in dollars per share)	$ 18.88
Weighted- Average Remaining Contractual Life (Year)	5 years 8 months 23 days
Weighted- Average Exercise Price (in dollars per share)	$ 16.94
Options Exercisable (in shares) \| shares	2,518,197
Weighted- Average Exercise Price of Options Exercisable	$ 16.91
Exercise Price Range 5
Options Outstanding (in shares) \| shares	3,045,374
Range of Exercise Prices, Lower Limit (in dollars per share)	$ 18.26
Range of Exercise Prices, Upper Limit (in dollars per share)	$ 24.97
Weighted- Average Remaining Contractual Life (Year)	6 years 6 months 21 days
Weighted- Average Exercise Price (in dollars per share)	$ 23.04
Options Exercisable (in shares) \| shares	2,276,351
Weighted- Average Exercise Price of Options Exercisable	$ 23.17
Exercise Price Range 6
Options Outstanding (in shares) \| shares	3,102,637
Exercise Prices	$ 25.02
Weighted- Average Remaining Contractual Life (Year)	7 years 9 months 3 days
Weighted- Average Exercise Price (in dollars per share)	$ 25.02
Options Exercisable (in shares) \| shares	1,619,032
Weighted- Average Exercise Price of Options Exercisable	$ 25.02
Exercise Price Range 7
Options Outstanding (in shares) \| shares	1,700,358
Range of Exercise Prices, Lower Limit (in dollars per share)	$ 25.06
Range of Exercise Prices, Upper Limit (in dollars per share)	$ 39.00
Weighted- Average Remaining Contractual Life (Year)	5 years 2 months 23 days
Weighted- Average Exercise Price (in dollars per share)	$ 30.53
Options Exercisable (in shares) \| shares	1,533,485
Weighted- Average Exercise Price of Options Exercisable	$ 30.52

Income Taxes - Additional Information (Details) - USD ($)			12 Months Ended
	Jun. 29, 2020	Mar. 27, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Research			$ 55,789,000	$ 49,683,000
Unrecognized Tax Benefits, Ending Balance			9,631,000	$ 7,406,000	$ 4,784,000	$ 2,385,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total			0
Net operating loss carryback period		5 years
Suspension of taxable income limitation percentage for operating loss carryforward		80.00%
California Franchise Tax Board \| Minimum
Operating Loss Carryforwards [Line Items]
Adjusted gross income for disallowance of net operating loss deductions	$ 1,000,000.0
California Franchise Tax Board \| Maximum
Operating Loss Carryforwards [Line Items]
Business credit offset amount	$ 5,000,000.0
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Total			1,200,000,000
Expiring Operating Loss Carryforwards			$ 547,400,000
Net operating loss carryforwards expiration year			2021
Indefinite Operating Loss Carryforwards			$ 664,200,000
Taxable income limitation percentage for operating loss carryforward			80.00%
Deferred Tax Assets, Tax Credit Carryforwards, Research			$ 45,300,000
Research and development credit carryforwards expiration year			2022
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Total			$ 743,400,000
Net operating loss carryforwards expiration year			2028
Deferred Tax Assets, Tax Credit Carryforwards, Research			$ 20,400,000
Research and development credit carryforwards expiration year			2023

Income Taxes - Summary of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 7,406	$ 4,784	$ 2,385
Additions for tax positions of prior years	107	341	147
Additions based on tax positions related to current year	2,118	2,281	2,252
Balance at end of year	$ 9,631	$ 7,406	$ 4,784

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

2.	Summary of Significant Accounting Policies

Principles of Consolidation

Use of Estimates

Cash, Cash Equivalents and Short-term Investments

Cash and cash equivalents consist of cash and highly liquid investments with contractual maturities of three months or less from the original purchase date.

Fair Value of Financial Instruments

Concentration of Credit Risk

The following table includes the percentage of net product sales and accounts receivable balances for our three major Customers, each of which comprised 10% or more of our net product sales:

	Net Product Sales			Accounts Receivable
	Year Ended December 31, 2021			As of December 31, 2021
Customer A		44.7	%		50.2	%
Customer B		34.9	%		33.8	%
Customer C		19.2	%		15.3	%
Total		98.8	%		99.3	%

Accounts Receivable, Net

Inventory

Property and Equipment

Impairment of Long-Lived Assets

Leases

Revenue Recognition

Product Sales

Our Products are distributed in the U.S. through a limited number of Customers that resell to healthcare providers and hospitals, the end users of our Products.

Product Sales Allowances

•

Distributor Fees—We offer contractually determined discounts to our Customers. These discounts are paid no later than two months after the quarter in which product was shipped.

•

Accrued Clinical Liabilities

Research and Development Expense

Patent Costs

Stock-Based Compensation Expense

Warrants

Income Taxes

Comprehensive Loss

Net Loss per Share

	December 31,
	2021		2020		2019
Stock options outstanding		18,944		18,912		16,665
Restricted stock units outstanding		2,803		603		—
Warrants outstanding		—		220		508
Shares of common stock underlying convertible notes outstanding		9,819		9,510		8,960

Recent Accounting Pronouncements

Adopted in 2021

Adopted in 2022

Equity Incentive Plans

12 Months Ended

Dec. 31, 2021