0001564590-21-042362 | 10-Q | XBRL Viewer | Heron Therapeutics INC DE

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2021	Jul. 29, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Trading Symbol	HRTX
Entity Registrant Name	HERON THERAPEUTICS, INC. /DE/
Entity Central Index Key	0000818033
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		101,909,490
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity File Number	001-33221
Entity Tax Identification Number	94-2875566
Entity Address, Address Line One	4242 Campus Point Court
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92121
City Area Code	858
Local Phone Number	251-4400
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, par value $0.01 per share
Security Exchange Name	NASDAQ

Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 191,173	$ 105,138
Short-term investments	66,505	103,353
Accounts receivable, net	42,615	41,850
Inventory	42,800	41,905
Prepaid expenses and other current assets	23,733	21,950
Total current assets	366,826	314,196
Property and equipment, net	22,175	22,737
Right-of-use lease assets	14,903	16,277
Other assets	346	346
Total assets	404,250	353,556
Current liabilities:
Accounts payable	11,242	525
Accrued clinical and manufacturing liabilities	23,907	49,962
Accrued payroll and employee liabilities	13,681	13,597
Other accrued liabilities	30,151	28,369
Current lease liabilities	3,162	2,997
Convertible notes payable to related parties, net of discount		7,053
Total current liabilities	82,143	102,503
Non-current lease liabilities	13,013	14,561
Non-current convertible notes payable, net	148,982
Total liabilities	244,138	117,064
Stockholders’ equity:
Common stock	1,019	913
Additional paid-in capital	1,665,429	1,628,070
Accumulated other comprehensive income	41	257
Accumulated deficit	(1,506,377)	(1,392,748)
Total stockholders’ equity	160,112	236,492
Total liabilities and stockholders’ equity	$ 404,250	$ 353,556

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues:
Net product sales	$ 22,443	$ 22,668	$ 42,461	$ 48,068
Operating expenses:
Cost of product sales	14,522	9,005	23,729	19,627
Research and development	35,233	44,004	73,349	80,898
General and administrative	10,907	9,819	20,480	20,241
Sales and marketing	22,250	15,589	37,486	35,785
Total operating expenses	82,912	78,417	155,044	156,551
Loss from operations	(60,469)	(55,749)	(112,583)	(108,483)
Other income (expense)	(546)	559	(1,046)	1,714
Net loss	(61,015)	(55,190)	(113,629)	(106,769)
Other comprehensive income (loss):
Unrealized gains (losses) on short-term investments	(80)	245	(216)	868
Comprehensive loss	$ (61,095)	$ (54,945)	$ (113,845)	$ (105,901)
Basic and diluted net loss per share	$ (0.62)	$ (0.61)	$ (1.20)	$ (1.18)
Shares used in computing basic and diluted net loss per share	98,459	90,753	94,943	90,581

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Balance at Dec. 31, 2019	$ 403,835	$ 903	$ 1,568,317	$ 85	$ (1,165,470)
Balance (in shares) at Dec. 31, 2019		90,304,000
Conversion benefit included in Convertible Notes issued	108		108
Issuance of common stock under equity incentive plan	504		504
Issuance of common stock under equity incentive plan (in shares)		70,000
Issuance of common stock on exercise of warrants	3	$ 3
Issuance of common stock on exercise of warrants (in shares)		268,000
Stock-based compensation expense	11,974		11,974
Net loss	(51,579)				(51,579)
Net unrealized gain (loss) on short-term investments	623			623
Comprehensive loss	(50,956)
Balance at Mar. 31, 2020	365,468	$ 906	1,580,903	708	(1,217,049)
Balance (in shares) at Mar. 31, 2020		90,642,000
Balance at Dec. 31, 2019	403,835	$ 903	1,568,317	85	(1,165,470)
Balance (in shares) at Dec. 31, 2019		90,304,000
Net loss	(106,769)
Net unrealized gain (loss) on short-term investments	868
Comprehensive loss	(105,901)
Balance at Jun. 30, 2020	324,058	$ 908	1,594,436	953	(1,272,239)
Balance (in shares) at Jun. 30, 2020		90,820,000
Balance at Mar. 31, 2020	365,468	$ 906	1,580,903	708	(1,217,049)
Balance (in shares) at Mar. 31, 2020		90,642,000
Conversion benefit included in Convertible Notes issued	109		109
Issuance of common stock under equity incentive plan	805	$ 1	804
Issuance of common stock under equity incentive plan (in shares)		54,000
Issuance of common stock on under the employee stock purchase plan	1,507	$ 1	1,506
Issuance of common stock on under the employee stock purchase plan (in shares)		124,000
Stock-based compensation expense	11,114		11,114
Net loss	(55,190)				(55,190)
Net unrealized gain (loss) on short-term investments	245			245
Comprehensive loss	(54,945)
Balance at Jun. 30, 2020	324,058	$ 908	1,594,436	953	(1,272,239)
Balance (in shares) at Jun. 30, 2020		90,820,000
Balance at Dec. 31, 2020	236,492	$ 913	1,628,070	257	(1,392,748)
Balance (in shares) at Dec. 31, 2020		91,310,000
Conversion benefit included in Convertible Notes issued	114		114
Issuance of common stock under equity incentive plan	883	$ 1	882
Issuance of common stock under equity incentive plan (in shares)		97,000
Stock-based compensation expense	11,486		11,486
Net loss	(52,614)				(52,614)
Net unrealized gain (loss) on short-term investments	(136)			(136)
Comprehensive loss	(52,750)
Balance at Mar. 31, 2021	196,225	$ 914	1,640,552	121	(1,445,362)
Balance (in shares) at Mar. 31, 2021		91,407,000
Balance at Dec. 31, 2020	$ 236,492	$ 913	1,628,070	257	(1,392,748)
Balance (in shares) at Dec. 31, 2020		91,310,000
Issuance of common stock on exercise of stock options (in shares)	357,839
Net loss	$ (113,629)
Net unrealized gain (loss) on short-term investments	(216)
Comprehensive loss	(113,845)
Balance at Jun. 30, 2021	160,112	$ 1,019	1,665,429	41	(1,506,377)
Balance (in shares) at Jun. 30, 2021		101,874,000
Balance at Mar. 31, 2021	196,225	$ 914	1,640,552	121	(1,445,362)
Balance (in shares) at Mar. 31, 2021		91,407,000
Conversion benefit included in Convertible Notes issued	116		116
Issuance of common stock under equity incentive plan	4,218	$ 4	4,214
Issuance of common stock under equity incentive plan (in shares)		313,000
Issuance of common stock on under the employee stock purchase plan	1,529	$ 1	1,528
Issuance of common stock on under the employee stock purchase plan (in shares)		110,000
Issuance of common stock on exercise of warrants		$ 2	(2)
Issuance of common stock on exercise of warrants (in shares)		195,000
Issuance of common stock on conversion of notes	7,878	$ 98	7,780
Issuance of common stock on conversion of notes (in shares)		9,849,000
Stock-based compensation expense	11,241		11,241
Net loss	(61,015)				(61,015)
Net unrealized gain (loss) on short-term investments	(80)			(80)
Comprehensive loss	(61,095)
Balance at Jun. 30, 2021	$ 160,112	$ 1,019	$ 1,665,429	$ 41	$ (1,506,377)
Balance (in shares) at Jun. 30, 2021		101,874,000

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating activities:
Net loss	$ (113,629)	$ (106,769)
Adjustments to reconcile net loss to net cash used for operating activities:
Stock-based compensation expense	22,727	23,088
Depreciation and amortization	1,473	1,366
Amortization of debt discount	785	645
Amortization of premium (accretion of discount) on short-term investments	178	(82)
Impairment of property and equipment	190	53
Change in operating assets and liabilities:
Accounts receivable	(765)	2,377
Inventory	(895)	(16,474)
Prepaid expenses and other assets	(1,783)	10,136
Accounts payable	10,717	15,700
Accrued clinical and manufacturing liabilities	(26,055)	(4,441)
Accrued payroll and employee liabilities	84	(4,055)
Other accrued liabilities	2,043	(11,756)
Net cash used for operating activities	(104,930)	(90,212)
Investing activities:
Purchases of short-term investments	(62,046)	(66,915)
Maturities and sales of short-term investments	98,500	166,825
Purchases of property and equipment	(1,101)	(3,687)
Net cash provided by investing activities	35,353	96,223
Financing activities:
Net proceeds from convertible note financing	148,982
Proceeds from issuance of common stock under equity incentive plan	5,101	1,309
Proceeds from purchases under the Employee Stock Purchase Plan	1,529	1,507
Proceeds from warrant exercises		3
Net cash provided by financing activities	155,612	2,819
Net increase in cash and cash equivalents	86,035	8,830
Cash and cash equivalents at beginning of year	105,138	71,898
Cash and cash equivalents at end of period	$ 191,173	$ 80,728

Business

6 Months Ended

Jun. 30, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Business

1. Business

We are a commercial-stage biotechnology company focused on improving the lives of patients by developing best-in-class treatments to address some of the most important unmet patient needs. Our advanced science, patented technologies, and innovative approach to drug discovery and development have allowed us to create and commercialize a portfolio of products that aim to advance the standard of care for acute care and oncology patients.

In August 2016, our first commercial product, SUSTOL (granisetron) extended-release injection (“SUSTOL”), was approved by the U.S. Food and Drug Administration (“FDA”). SUSTOL is indicated in combination with other antiemetics in adults for the prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of moderately emetogenic chemotherapy (MEC) or anthracycline and cyclophosphamide (AC) combination chemotherapy regimens. SUSTOL is an extended-release, injectable 5-hydroxytryptamine type 3 receptor antagonist that utilizes our proprietary Biochronomer drug delivery technology to maintain therapeutic levels of granisetron for ≥5 days. We commenced commercial sales of SUSTOL in the U.S. in October 2016.

In November 2017, our second commercial product, CINVANTI (aprepitant) injectable emulsion (“CINVANTI”), was approved by the FDA. In October 2019, the FDA approved our supplemental New Drug Application (“sNDA”) for CINVANTI to expand the indication and recommended dosage to include the 130 mg single-dose regimen for patients receiving moderately emetogenic cancer chemotherapy (“MEC”). CINVANTI, in combination with other antiemetic agents, is indicated in adults for the prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy (HEC) including high-dose cisplatin as a single-dose regimen, delayed nausea and vomiting associated with initial and repeat courses of moderately emetogenic cancer chemotherapy (MEC) as a single-dose regimen, and nausea and vomiting associated with initial and repeat courses of MEC as a 3-day regimen. CINVANTI is an intravenous (“IV”) formulation of aprepitant, a substance P/neurokinin-1 (“NK₁”) receptor antagonist. We commenced commercial sales of CINVANTI in the U.S. in January 2018. In February 2019, the FDA approved our sNDA for CINVANTI, for IV use, which expanded the administration of CINVANTI beyond the initially approved administration method (a 30-minute IV infusion) to include a 2-minute IV injection.

In May 2021, our third commercial product, ZYNRELEF (bupivacaine and meloxicam) extended-release solution (“ZYNRELEF”), was approved by the FDA. ZYNRELEF is indicated for use in adults for soft tissue or periarticular instillation to produce postsurgical analgesia for up to 72 hours after bunionectomy, open inguinal herniorrhaphy and total knee arthroplasty. ZYNRELEF is a dual-acting local anesthetic that delivers a fixed-dose combination of the local anesthetic bupivacaine and a low dose of nonsteroidal anti-inflammatory drug meloxicam. ZYNRELEF is the first and only modified-release local anesthetic to be classified by the FDA as an extended-release product because ZYNRELEF demonstrated in Phase 3 studies significantly reduced pain and significantly increased proportion of patients requiring no opioids through the first 72 hours following surgery compared to bupivacaine solution, the current standard-of-care local anesthetic for postoperative pain control. We commenced commercial sales of ZYNRELEF in the U.S. in July 2021.

In September 2020, ZYNRELEFwas granted a marketing authorization by the European Commission. As of January 1, 2021, ZYNRELEF is approved in 31 European countries including the countries of the European Union and European Economic Area and the United Kingdom. ZYNRELEF is indicated for the treatment of somatic postoperative pain from small- to medium-sized surgical wounds in adults. As we build large-scale manufacturing capacity to meet the anticipated commercial demand in the U.S. and the rest of the world, we are developing a coordinated global marketing strategy. At this time, we anticipate making ZYNRELEF available to patients in Europe during 2022.

HTX-011 (ZYNRELEF in the U.S. and Europe) is an investigational agent in Canada. Our New Drug Submission for HTX-011 for the management of postoperative pain was accepted by Health Canada in November 2019. In April 2021, we responded to a list of questions received from Health Canada, and we anticipate up to a 300-day review period following screening of our responses.

HTX-034, our next-generation product candidate for postoperative pain management, is an investigational non-opioid, fixed-dose combination, extended‑release solution of the local anesthetic bupivacaine, the nonsteroidal anti-inflammatory drug meloxicam and an additional agent that further potentiates the activity of bupivacaine. HTX-034 is formulated in the same proprietary polymer as ZYNRELEF. By combining two different mechanisms that each enhance the activity of the local anesthetic bupivacaine, HTX-034 is designed to provide superior and prolonged analgesia. Local administration of HTX-034 in a validated preclinical postoperative pain model resulted in sustained analgesia for 7 days. In May 2020, we initiated a Phase 1b/2 clinical study in patients undergoing bunionectomy of HTX-034. In the Phase 1b portion of this Phase 1b/2 double-blind, randomized, active-controlled, dose-escalation study in 33 patients undergoing bunionectomy, the reduction in pain intensity observed was greater with the lowest dose of HTX-034 evaluated (containing 21.7 mg of bupivacaine plus meloxicam and aprepitant) than with the bupivacaine 50 mg solution through 96 hours. In addition, 45.5% of HTX-034 patients remained opioid-free through Day 15 with median opioid consumption of 2.5 milligram morphine equivalents (same as one 5 mg oxycodone pill) through 72-hours, a 71% reduction compared to bupivacaine solution. We initiated the expanded Phase 2 portion of the study for HTX-034 in the first quarter of 2021.

HTX-019 is an investigational agent for the prevention of postoperative nausea and vomiting (“PONV”). HTX-019 is an IV injectable emulsion formulation designed to directly deliver aprepitant, the active ingredient in EMEND^® (aprepitant) capsules, which is the only NK₁ receptor antagonist approved in the U.S. for the prevention of PONV in adults. The FDA-approved dose of oral EMEND is 40 mg for PONV, which is given within 3 hours prior to induction of anesthesia for surgery. An Investigational New Drug application for HTX-019 for PONV was approved by the FDA in late September 2020. In a Phase 1 clinical trial, 32 mg of HTX-019 as a 30-second IV injection was demonstrated to be bioequivalent to oral aprepitant 40 mg. An NDA for HTX-019 is planned in late 2021 for prevention of PONV in adults.

As of June 30, 2021 we had $257.7 million in cash, cash equivalents and short-term investments. We have incurred significant operating losses and negative cash flows from operations. Management believes that the Company’s existing cash, cash equivalents and short-term investments will be sufficient to meet the Company’s anticipated cash requirements for at least one year from the date this Quarterly Report on Form 10-Q is filed with the U.S. Securities and Exchange Commission (“SEC”).

Basis of Presentation

6 Months Ended

Jun. 30, 2021

Accounting Policies [Abstract]

Basis of Presentation

2. Basis of Presentation

The accompanying condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the U.S. (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the three and six months ended June 30, 2021 are not necessarily indicative of the results that may be expected for other quarters or the year ending December 31, 2021. The condensed consolidated balance sheet as of December 31, 2020 has been derived from the audited financial statements as of that date, but does not include all of the information and disclosures required by GAAP. For more complete financial information, these condensed consolidated financial statements and the notes thereto should be read in conjunction with the audited financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2020, which was filed with the SEC on February 24, 2021.

Accounting Policies

6 Months Ended

Jun. 30, 2021

Accounting Policies [Abstract]

Accounting Policies

3. Accounting Policies

Principles of Consolidation

The accompanying condensed 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 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 condensed 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 condensed 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). 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.

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 and SUSTOL 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 CINVANTI and SUSTOL.

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
	Three Months Ended June 30, 2021			Six Months Ended June 30, 2021			As of June 30, 2021
Customer A		50.2	%		48.9	%		48.9	%
Customer B		30.9	%		31.7	%		37.4	%
Customer C		18.1	%		18.5	%		13.3	%
Total		99.2	%		99.1	%		99.6	%

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 launch of CINVANTI in January 2018. 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 we 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 June 30, 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 June 30, 2021 and December 31, 2020, we determined that an allowance for credit losses was not required. For the three and six months ended June 30, 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.

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 condensed 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

In May 2014, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update No. 2014-09, 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

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

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 performed 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.

Net product sales for the three and six months ended June 30, 2021 were $22.4 million and $42.5 million, respectively, compared to $22.7 million and $48.1 million, respectively, for the same periods in 2020. For the three and six months ended June 30, 2021, net products sales of CINVANTI were $19.7 million and $38.2 million, respectively, compared to $22.6 million and $47.8 million, respectively, for the same periods in 2020. For the three and six months ended June 30, 2021, net product sales of SUSTOL were $2.7 million and $4.3 million, respectively, compared to $0.1 million and $0.3 million, respectively, for the same periods in 2020.

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 condensed consolidated balance sheets (in thousands):

	Product Returns			Distributor Fees			Discounts, Rebates and Administrative Fees			Total
Balance at December 31, 2020	$	2,704		$	3,930		$	17,937		$	24,571
Provision		375			8,986			72,010			81,371
Payments/credits		(247	)		(8,749	)		(72,510	)		(81,506	)
Balance at June 30, 2021	$	2,832		$	4,167		$	17,437		$	24,436

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 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 unaudited condensed 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):

	June 30,
	2021		2020
Stock options outstanding		18,307		16,306
Restricted stock units outstanding		654		—
Warrants outstanding		25		220
Shares of common stock underlying convertible notes outstanding		9,819		9,231

Recent Accounting Pronouncements

Adopted in 2021

In December 2019, the FASB issued 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.

Not Yet Adopted

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. We plan to adopt the provisions of ASU 2020-06 in the first quarter of 2022 using the modified retrospective adoption approach and we are currently evaluating the impact on our results of operations, financial condition and related disclosures.

Fair Value Measurements

6 Months Ended

Jun. 30, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements

4. 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 Accounting Standards Codification (“ASC”) Topic 820, Fair Value Measurements and 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 such assets were as follows (in thousands):

			Fair Value Measurements at Reporting Date Using
	Balance at June 30, 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	$	191,173	$	191,173	$	—	$	—
U.S. treasury bills and government agency obligations		10,056		10,056		—		—
U.S. corporate debt securities		19,017		—		19,017		—
Foreign corporate debt securities		4,447		—		4,447		—
U.S. commercial paper		4,997		—		4,997		—
Foreign commercial paper		27,988		—		27,988		—
Total	$	257,678	$	201,229	$	56,449	$	—

			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 June 30, 2021, short-term investments included $66.5 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 June 30, 2021 and December 31, 2020 are included in cash and cash equivalents on the condensed consolidated balance sheets.

A company may elect to use fair value to measure accounts and loans receivable, available-for-sale and held-to-maturity securities, equity method investments, accounts payable, guarantees and issued debt. Other eligible items include firm commitments for financial instruments that otherwise would not be recognized at inception and non-cash warranty obligations where a warrantor is permitted to pay a third party to provide the warranty goods or services. If the use of fair value is elected, any upfront costs and fees related to the item such as debt issuance costs must be recognized in earnings and cannot be deferred. The fair value election is irrevocable and generally made on an instrument-by-instrument basis, even if a company has similar instruments that it elects not to measure based on fair value. Unrealized gains and losses on existing items for which fair value has been elected are reported as a cumulative adjustment to beginning retained earnings and any changes in fair value are recognized in earnings. We have elected to not apply the fair value option to our financial assets and liabilities.

Financial instruments, including cash, 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. Our convertible notes outstanding at June 30, 2021 do not have a readily available ascertainable market value, however, the carrying value is considered to approximate its fair value.

- Definition

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

Short-term Investments

6 Months Ended

Jun. 30, 2021

Short Term Investments [Abstract]

Short-term Investments

5. Short-term Investments

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

	June 30, 2021
			Gross		Gross
	Amortized		Unrealized		Unrealized		Estimated
	Cost		Gains		Losses		Fair Value
U.S. treasury bills and government agency obligations	$	10,022	$	34	$	—	$	10,056
U.S. corporate debt securities		19,010		7		—		19,017
Foreign corporate debt securities		4,447		—		—		4,447
U.S. commercial paper		4,997		—		—		4,997
Foreign commercial paper		27,988		—		—		27,988
Total	$	66,464	$	41	$	—	$	66,505

	December 31, 2020
			Gross		Gross
	Amortized		Unrealized		Unrealized		Estimated
	Cost		Gains		Losses		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 during the three and six months ended June 30, 2021 and 2020.

Unrealized gains and losses associated with our investments are reported in accumulated other comprehensive loss. Realized gains and losses associated with our available-for-sale securities, if any, are reported in the statements of operations and comprehensive loss. We did not recognize any realized gains or losses during the three and six months ended June 30, 2021 and 2020.

Inventory

6 Months Ended

Jun. 30, 2021

Inventory Disclosure [Abstract]

Inventory

6. Inventory

Inventory consists of the following (in thousands):

	June 30, 2021		December 31, 2020
Raw materials	$	20,985	$	18,994
Work in process		14,732		6,847
Finished goods		7,083		16,064
Total inventory	$	42,800	$	41,905

As of June 30, 2021, total inventory included $33.9 million related to CINVANTI, $5.8 million related to ZYNRELEF and $3.1 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 three and six months ended June 30, 2021 included charges of $3.1 million resulting from the write-off of short-dated SUSTOL inventory.

Leases

6 Months Ended

Jun. 30, 2021

Leases [Abstract]

Leases

7. Leases

As of June 30, 2021, we had an operating lease for 73,328 square feet of laboratory and office space in San Diego, California, with a lease term that expires on December 31, 2025. We have one 5-year option to renew this lease on expiration. During the three and six months ended June 30, 2021, we recognized operating lease expense of $1.0 million and $2.0 million, respectively, and we paid $1.0 million and $2.0 million, respectively, for our operating lease.

Annual future minimum lease payments as of June 30, 2021 are as follows (in thousands):

2021	$	1,979
2022		4,058
2023		4,178
2024		4,274
2025		4,379
Thereafter		—
Total future minimum lease payments	$	18,868
Less: discount		(2,693	)
Total lease liabilities	$	16,175

Reorganization

6 Months Ended

Jun. 30, 2021

Reorganizations [Abstract]

Reorganization

8. Reorganization

In October 2020, we implemented changes to our organizational structure. In connection with the reorganization, 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 plan modifications.

The total expense for these activities was $5.6 million, $2.5 million primarily for severance and $3.1 million for non-cash, stock-based compensation expense, which was recognized during the fourth quarter of 2020. As of June 30, 2021, we have 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.

Convertible Notes

6 Months Ended

Jun. 30, 2021

Debt Disclosure [Abstract]

Convertible Notes

9. Convertible Notes

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 condensed 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 condensed 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 three and six months ended June 30, 2021, interest expense related to the Notes was $231,000, which included $212,000 related to the stated interest rate and $19,000 related to the amortization of debt issuance costs. As of June 30, 2021, the carrying value of the Notes was $149.0 million, which is comprised of the $150.0 million principal amount of the Notes outstanding, less debt issuance costs of $1.0 million.

Senior Secured Convertible Notes (“Convertible Notes”)

In April 2011, we entered into a securities purchase agreement for a private placement of up to $4.5 million in 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 waived their right to require us to maintain the effectiveness of the registration statement.

The Convertible Notes contained 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 amortized the resultant debt discount over the respective 10-year term of the Convertible Notes. During the six months ended June 30, 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 each of the three and six months ended June 30, 2021 and 2020, interest expense relating to the stated rate was $0.1 million and $0.2 million, respectively. For the three and six months ended June 30, 2021, interest expense relating to the amortization of the debt discount was $0.3 million and $0.8 million, respectively, compared to $0.3 million and $0.6 million, respectively, for the same periods in 2020.

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.

Stockholders' Equity

6 Months Ended

Jun. 30, 2021

Equity [Abstract]

Stockholders' Equity

10. Stockholders’ Equity

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 expired on June 30, 2021. During the three months ended June 30, 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 June 30, 2021, no warrants from the June 2014 public offering remain outstanding.

Option Plan Activity

The following table summarizes the stock option activity for the six months ended June 30, 2021:

	Shares (in thousands)			Weighted- average Exercise Price		Weighted- average Remaining Contractual Term (Years)
Outstanding at December 31, 2020		18,912		$	19.59		7.21
Granted		628		$	15.87
Exercised		(358	)	$	15.51
Expired and forfeited		(875	)	$	22.50
Outstanding at June 30, 2021		18,307		$	19.40		7.02

The following table summarizes the restricted stock unit activity for the six months ended June 30, 2021:

	Shares (in thousands)			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2020		603		$	15.84
Granted		150		$	15.29
Released		(77	)	$	15.98
Expired and forfeited		(22	)	$	16.06
Outstanding at June 30, 2021		654		$	15.69

For the six months ended June 30, 2021, 357,839 shares of common stock were issued pursuant to the exercise of stock options, resulting in net proceeds of $5.5 million.

Stock-based Compensation

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development	$	4,672	$	4,681	$	9,609	$	9,968
General and administrative		2,792		3,304		5,578		6,735
Sales and marketing		3,777		3,129		7,540		6,385
Total stock-based compensation expense	$	11,241	$	11,114	$	22,727	$	23,088

As of June 30, 2021, there was $97.6 million of total unrecognized compensation cost related to non-vested, stock-based payment awards granted under all of our equity compensation plans and all non-plan option grants. Total unrecognized compensation cost will be adjusted for future changes in estimated forfeitures. We expect to recognize this compensation cost over a weighted-average period of 2.6 years.

The fair value of RSUs is estimated based on the closing market price of our common stock on the date of the grant. RSUs generally vest quarterly over a four-year period.

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

	June 30,
	2021			2020
Risk-free interest rate		1.0	%		1.1	%
Dividend yield		0.0	%		0.0	%
Volatility		66.6	%		66.7	%
Expected life (years)		6			6

We estimated the fair value of each purchase right granted under our 1997 Employee Stock Purchase Plan, as amended, at the beginning of each new offering period using the Black-Scholes option pricing model with the following weighted-average assumptions:

	June 30,
	2021			2020
Risk-free interest rate		0.04	%		0.10	%
Dividend yield		0.0	%		0.0	%
Volatility		48.3	%		63.3	%
Expected life (months)		6			6

Income Taxes

6 Months Ended

Jun. 30, 2021

Income Tax Disclosure [Abstract]

Income Taxes

11. Income Taxes

Deferred income tax assets and liabilities are recognized for temporary differences between financial statements and income tax carrying values using tax rates in effect for the years such differences are expected to reverse. Due to uncertainties surrounding our ability to generate future taxable income and consequently realize such deferred income tax assets, a full valuation allowance has been established. We continue to maintain a full valuation allowance against our deferred tax assets as of June 30, 2021.

The impact of an uncertain income tax position on the income tax return must be recognized at the largest amount that is more likely than not to be sustained upon audit by the relevant tax authority. An uncertain income tax position will be recognized when it is more likely than not of being sustained. The disclosures regarding an uncertain income tax position included in our Annual Report on Form 10-K for the year ended December 31, 2020, which was filed with the SEC on February 24, 2021, continue to be accurate for the three and six months ended June 30, 2021.

- Definition

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.

+ References + Details

Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2021

Accounting Policies [Abstract]

Basis of Presentation

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.

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
	Three Months Ended June 30, 2021			Six Months Ended June 30, 2021			As of June 30, 2021
Customer A		50.2	%		48.9	%		48.9	%
Customer B		30.9	%		31.7	%		37.4	%
Customer C		18.1	%		18.5	%		13.3	%
Total		99.2	%		99.1	%		99.6	%

Accounts Receivable, Net

Inventory

Leases

Revenue Recognition

Product Sales

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

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.

•

	Product Returns			Distributor Fees			Discounts, Rebates and Administrative Fees			Total
Balance at December 31, 2020	$	2,704		$	3,930		$	17,937		$	24,571
Provision		375			8,986			72,010			81,371
Payments/credits		(247	)		(8,749	)		(72,510	)		(81,506	)
Balance at June 30, 2021	$	2,832		$	4,167		$	17,437		$	24,436

Comprehensive Loss

Net Loss per Share

	June 30,
	2021		2020
Stock options outstanding		18,307		16,306
Restricted stock units outstanding		654		—
Warrants outstanding		25		220
Shares of common stock underlying convertible notes outstanding		9,819		9,231

Recent Accounting Pronouncements

Adopted in 2021

Not Yet Adopted

Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2021

Accounting Policies [Abstract]

Percentage of Net Product Sales and Accounts Receivable Balance

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
	Three Months Ended June 30, 2021			Six Months Ended June 30, 2021			As of June 30, 2021
Customer A		50.2	%		48.9	%		48.9	%
Customer B		30.9	%		31.7	%		37.4	%
Customer C		18.1	%		18.5	%		13.3	%
Total		99.2	%		99.1	%		99.6	%

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

	Product Returns			Distributor Fees			Discounts, Rebates and Administrative Fees			Total
Balance at December 31, 2020	$	2,704		$	3,930		$	17,937		$	24,571
Provision		375			8,986			72,010			81,371
Payments/credits		(247	)		(8,749	)		(72,510	)		(81,506	)
Balance at June 30, 2021	$	2,832		$	4,167		$	17,437		$	24,436

Common Stock Equivalents Excluded From Computation of Net Loss Per Share

	June 30,
	2021		2020
Stock options outstanding		18,307		16,306
Restricted stock units outstanding		654		—
Warrants outstanding		25		220
Shares of common stock underlying convertible notes outstanding		9,819		9,231

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 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 such assets were as follows (in thousands):

			Fair Value Measurements at Reporting Date Using
	Balance at June 30, 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	$	191,173	$	191,173	$	—	$	—
U.S. treasury bills and government agency obligations		10,056		10,056		—		—
U.S. corporate debt securities		19,017		—		19,017		—
Foreign corporate debt securities		4,447		—		4,447		—
U.S. commercial paper		4,997		—		4,997		—
Foreign commercial paper		27,988		—		27,988		—
Total	$	257,678	$	201,229	$	56,449	$	—

			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	$	—

Short-term Investments (Tables)

6 Months Ended

Jun. 30, 2021

Short Term Investments [Abstract]

Summary of Short-term Investments

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

	June 30, 2021
			Gross		Gross
	Amortized		Unrealized		Unrealized		Estimated
	Cost		Gains		Losses		Fair Value
U.S. treasury bills and government agency obligations	$	10,022	$	34	$	—	$	10,056
U.S. corporate debt securities		19,010		7		—		19,017
Foreign corporate debt securities		4,447		—		—		4,447
U.S. commercial paper		4,997		—		—		4,997
Foreign commercial paper		27,988		—		—		27,988
Total	$	66,464	$	41	$	—	$	66,505

	December 31, 2020
			Gross		Gross
	Amortized		Unrealized		Unrealized		Estimated
	Cost		Gains		Losses		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

Inventory (Tables)

6 Months Ended

Jun. 30, 2021

Inventory Disclosure [Abstract]

Schedule of Inventory

Inventory consists of the following (in thousands):

	June 30, 2021		December 31, 2020
Raw materials	$	20,985	$	18,994
Work in process		14,732		6,847
Finished goods		7,083		16,064
Total inventory	$	42,800	$	41,905

Leases (Tables)

6 Months Ended

Jun. 30, 2021

Leases [Abstract]

Summary of Future Minimum Lease Payments

Annual future minimum lease payments as of June 30, 2021 are as follows (in thousands):

2021	$	1,979
2022		4,058
2023		4,178
2024		4,274
2025		4,379
Thereafter		—
Total future minimum lease payments	$	18,868
Less: discount		(2,693	)
Total lease liabilities	$	16,175

Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 2021

Equity [Abstract]

Summary of Stock Option Activity

The following table summarizes the stock option activity for the six months ended June 30, 2021:

	Shares (in thousands)			Weighted- average Exercise Price		Weighted- average Remaining Contractual Term (Years)
Outstanding at December 31, 2020		18,912		$	19.59		7.21
Granted		628		$	15.87
Exercised		(358	)	$	15.51
Expired and forfeited		(875	)	$	22.50
Outstanding at June 30, 2021		18,307		$	19.40		7.02

Summary of Restricted Stock Unit Activity

The following table summarizes the restricted stock unit activity for the six months ended June 30, 2021:

	Shares (in thousands)			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2020		603		$	15.84
Granted		150		$	15.29
Released		(77	)	$	15.98
Expired and forfeited		(22	)	$	16.06
Outstanding at June 30, 2021		654		$	15.69

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

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development	$	4,672	$	4,681	$	9,609	$	9,968
General and administrative		2,792		3,304		5,578		6,735
Sales and marketing		3,777		3,129		7,540		6,385
Total stock-based compensation expense	$	11,241	$	11,114	$	22,727	$	23,088

Summary of Fair Value of Option Grant on Grant Date Using Black-Scholes Option Pricing Model

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

	June 30,
	2021			2020
Risk-free interest rate		1.0	%		1.1	%
Dividend yield		0.0	%		0.0	%
Volatility		66.6	%		66.7	%
Expected life (years)		6			6

Summary of Fair Value of Purchase Right Granted Using Black-Scholes Option Pricing Model

	June 30,
	2021			2020
Risk-free interest rate		0.04	%		0.10	%
Dividend yield		0.0	%		0.0	%
Volatility		48.3	%		63.3	%
Expected life (months)		6			6

Business - Additional Information (Details) $ in Millions	6 Months Ended
Business - Additional Information (Details) $ in Millions	Jun. 30, 2021 USD ($)	Jan. 01, 2021 Country
Business [Line Items]
Cash, cash equivalents and short-term investments \| $	$ 257.7
HTX-034 \| Europe
Business [Line Items]
Number of countries approved the drug \| Country		31
HTX-034
Business [Line Items]
Percentage of patients remained opioid free	45.50%
Percentage of reduction in pain intensity	71.00%

Accounting Policies - Percentage of Net Product Sales and Accounts Receivable Balance (Details) - Customer Concentration Risk	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2021
Revenue Benchmark
Product Information [Line Items]
Concentration risk percentage	99.20%	99.10%
Revenue Benchmark \| Largest Customer
Product Information [Line Items]
Concentration risk percentage	50.20%	48.90%
Revenue Benchmark \| Second Largest Customer
Product Information [Line Items]
Concentration risk percentage	30.90%	31.70%
Revenue Benchmark \| Third Largest Customer
Product Information [Line Items]
Concentration risk percentage	18.10%	18.50%
Accounts Receivable
Product Information [Line Items]
Concentration risk percentage		99.60%
Accounts Receivable \| Largest Customer
Product Information [Line Items]
Concentration risk percentage		48.90%
Accounts Receivable \| Second Largest Customer
Product Information [Line Items]
Concentration risk percentage		37.40%
Accounts Receivable \| Third Largest Customer
Product Information [Line Items]
Concentration risk percentage		13.30%

Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Product Information [Line Items]
Net product sales	$ 22,443	$ 22,668	$ 42,461	$ 48,068
Accounting Standards Update 2019-12
Product Information [Line Items]
Change in accounting principle, accounting standards update, adopted	true		true
Change in accounting principle, accounting standards update, immaterial effect	true		true
CINVANTI
Product Information [Line Items]
Net product sales	$ 19,700	22,600	$ 38,200	47,800
SUSTOL
Product Information [Line Items]
Net product sales	$ 2,700	$ 100	$ 4,300	$ 300

- Definition

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

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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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+ Details

Accounting Policies - Summary of Activity to Product Returns, Distributor Fees and Discounts, Rebates and Administrative Fees (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)
Product Information [Line Items]
Balance	$ 24,571
Provision	81,371
Payments/credits	(81,506)
Balance	24,436
Product Returns
Product Information [Line Items]
Balance	2,704
Provision	375
Payments/credits	(247)
Balance	2,832
Distributor Fees
Product Information [Line Items]
Balance	3,930
Provision	8,986
Payments/credits	(8,749)
Balance	4,167
Discounts, Rebates and Administrative Fees
Product Information [Line Items]
Balance	17,937
Provision	72,010
Payments/credits	(72,510)
Balance	$ 17,437

Accounting Policies - Common Stock Equivalents Excluded From Computation of Net Loss Per Share (Details) - shares shares in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Share-based Payment Arrangement, Option
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded (in shares)	18,307	16,306
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded (in shares)	654
Warrant
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded (in shares)	25	220
Convertible Debt Securities
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded (in shares)	9,819	9,231

Fair Value Measurements - Schedule of Financial Assets Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 66,505	$ 103,353
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	10,056	20,276
U.S. Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	19,017	11,547
Foreign Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	4,447	15,557
U.S. Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	4,997	13,997
Fair Value, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	257,678	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	27,988	83,966
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	10,056	20,276
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	19,017	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	4,447	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	4,997	27,996
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	201,229	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	10,056	20,276
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	56,449	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	27,988	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	19,017	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	4,447	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	4,997	27,996
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	191,173	49,149
Fair Value, Recurring \| Cash and Money Market Funds \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and money market funds	$ 191,173	$ 49,149

Fair Value Measurements - Additional Information (Details) - USD ($)	6 Months Ended
	Jun. 30, 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		$ 55,900,000
Available for sale securities with contractual maturities of three months to one year.	$ 66,500,000	$ 103,400,000

Short-term Investments - Summary of Short-term Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	$ 66,464	$ 103,096
Available-for-sale securities, gross unrealized gains	41	257
Available-for-sale securities	66,505	103,353
U.S. Treasury Bills and Government Agency Obligations
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	10,022	20,110
Available-for-sale securities, gross unrealized gains	34	166
Available-for-sale securities	10,056	20,276
U.S. Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	19,010	11,505
Available-for-sale securities, gross unrealized gains	7	42
Available-for-sale securities	19,017	11,547
Foreign Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	4,447	15,508
Available-for-sale securities, gross unrealized gains		49
Available-for-sale securities	4,447	15,557
U.S. Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	4,997	13,997
Available-for-sale securities	4,997	13,997
Foreign Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	27,988	41,976
Available-for-sale securities	$ 27,988	$ 41,976

Short-term Investments - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Short Term Investments [Abstract]
Debt securities, impairment losses	$ 0	$ 0	$ 0	$ 0
Debt securities, available-for-sale, realized gain (loss)	$ 0	$ 0	$ 0	$ 0

Inventory - Schedule of Inventory (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 20,985	$ 18,994
Work in process	14,732	6,847
Finished goods	7,083	16,064
Total inventory	$ 42,800	$ 41,905

Inventory - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Inventory [Line Items]
Total inventory	$ 42,800	$ 42,800	$ 41,905
CINVANTI
Inventory [Line Items]
Total inventory	33,900	33,900	37,800
SUSTOL
Inventory [Line Items]
Total inventory	3,100	3,100	$ 4,100
Cost of product sales, charges	3,100	3,100
ZYNRELEF
Inventory [Line Items]
Total inventory	$ 5,800	$ 5,800

Leases - Additional Information (Details) - San Diego, California $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2021 USD ($) ft²	Jun. 30, 2021 USD ($) ft²
Lessee Lease Description [Line Items]
Area of real estate property \| ft²	73,328	73,328
Lease expiration date		Dec. 31, 2025
Lessee, operating lease, renewal term	5 years	5 years
Lessee, operating lease, existence of option to extend		true
Operating lease expense	$ 1.0	$ 2.0
Operating lease cash payments	$ 1.0	$ 2.0

Leases - Summary of Future Minimum Lease Payments (Details) $ in Thousands	Jun. 30, 2021 USD ($)
Leases [Abstract]
2021	$ 1,979
2022	4,058
2023	4,178
2024	4,274
2025	4,379
Total future minimum lease payments	18,868
Less: discount	(2,693)
Total lease liabilities	$ 16,175

Reorganization - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended
	Oct. 31, 2020	Jun. 30, 2021
Restructuring charges, total	$ 5.6
Employee Severance
Restructuring charges, total	2.5
Payments for restructuring charges		$ 2.5
Accelerated Non-Cash Stock Option Expense
Restructuring charges, total	$ 3.1

Convertible Notes - Additional Information (Details) - USD ($)		1 Months Ended		3 Months Ended		6 Months Ended
	Jul. 29, 2011	May 31, 2021	Apr. 30, 2011	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Debt Instrument [Line Items]
Net proceeds from convertible note financing						$ 148,982,000
Amortization of debt discount						785,000	$ 645,000
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
Notes
Debt Instrument [Line Items]
Convertible debt issuable in connection with private placement		$ 150,000,000.0
Net proceeds from convertible note 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%		1.60%
Interest expense				$ 231,000		$ 231,000
Interest expense, debt, excluding amortization				212,000		212,000
Amortization of debt issuance costs				19,000		19,000
Carrying value of debt				149,000,000.0		149,000,000.0
Debt instrument, face amount				150,000,000.0		150,000,000.0
Debt issuance costs				1,000,000.0		1,000,000.0
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 note 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				100,000	$ 100,000	200,000	200,000
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				$ 300,000	$ 300,000	$ 800,000	$ 600,000
Convertible Notes \| Common Stock
Debt Instrument [Line Items]
Debt instrument, number of shares issued for convertible notes			1,250

Stockholders' Equity - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2021	Jun. 30, 2021
Class Of Stock [Line Items]
Shares of common stock issued pursuant to exercise of stock options			357,839
Proceeds from stock options exercised			$ 5,500,000
Total unrecognized compensation cost related to non-vested, stock-based payment awards		$ 97,600,000	$ 97,600,000
Total unrecognized compensation cost, expect to recognize over weighted average period			2 years 7 months 6 days
Restricted Stock Units
Class Of Stock [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period			4 years
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		195,574,000
Stock issued during period, shares, warrants exercised		195,461,000
Proceeds from issuance of warrants		$ 0
Class of warrant or right, outstanding		0	0

Stockholders' Equity - Summary of Stock Option Activity (Details) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Equity [Abstract]
Number of shares outstanding	18,912,000
Number of shares granted	628,000
Number of shares exercised	(357,839)
Number of shares expired and forfeited	(875,000)
Number of shares outstanding	18,307,000	18,912,000
Number of shares outstanding, weighted average exercise price	$ 19.59
Number of shares granted, weighted average exercise price	15.87
Number of shares exercised, weighted average exercise price	15.51
Number of shares expired and forfeited, weighted average exercise price	22.50
Number of shares outstanding, weighted average exercise price	$ 19.40	$ 19.59
Number of shares outstanding, weighted average remaining contractual term (Year)	7 years 7 days	7 years 2 months 15 days

Stockholders' Equity - Summary of Restricted Stock Unit Activity (Details) - Restricted Stock Units shares in Thousands	6 Months Ended
	Jun. 30, 2021 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares outstanding \| shares	603
Number of shares granted \| shares	150
Number of shares released \| shares	(77)
Number of shares expired and forfeited \| shares	(22)
Number of shares outstanding \| shares	654
Number of shares outstanding, weighted average grant date fair value \| $ / shares	$ 15.84
Number of shares granted, weighted average grant date fair value \| $ / shares	15.29
Number of shares released, weighted average grant date fair value \| $ / shares	15.98
Number of shares expired and forfeited, weighted average grant date fair value \| $ / shares	16.06
Number of shares outstanding, weighted average grant date fair value \| $ / shares	$ 15.69

Stockholders' Equity - Summary of Stock-Based Compensation Expense related to Stock-Based Payment Awards Granted (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 11,241	$ 11,114	$ 22,727	$ 23,088
Research and Development Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	4,672	4,681	9,609	9,968
General and Administrative Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	2,792	3,304	5,578	6,735
Selling and Marketing Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 3,777	$ 3,129	$ 7,540	$ 6,385

Stockholders' Equity - Summary of Fair Value of Option Grant on Grant Date Using Black-Scholes Option Pricing Model (Details) - Share-based Payment Arrangement, Option	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	1.00%	1.10%
Dividend yield	0.00%	0.00%
Volatility	66.60%	66.70%
Expected life	6 years	6 years

Stockholders' Equity - Summary of Fair Value of Purchase Right Granted Using Black-Scholes Option Pricing Model (Details) - 1997 Employee Stock Purchase Plan	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	0.04%	0.10%
Dividend yield	0.00%	0.00%
Volatility	48.30%	63.30%
Expected life	6 months	6 months