Heron Therapeutics (HRTX) 10-Q 5 Aug 20 2020 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2020	Jul. 29, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2020
Document Fiscal Year Focus	2020
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		90,855,254
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

Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 80,728	$ 71,898
Short-term investments	220,114	319,074
Accounts receivable, net	37,502	39,879
Inventory	41,442	24,968
Prepaid expenses and other current assets	13,109	23,245
Total current assets	392,895	479,064
Property and equipment, net	21,886	19,618
Right-of-use lease assets	17,594	13,754
Other assets	346	346
Total assets	432,721	512,782
Current liabilities:
Accounts payable	18,458	2,758
Accrued clinical and manufacturing liabilities	30,173	34,614
Accrued payroll and employee liabilities	11,193	15,248
Other accrued liabilities	23,728	36,535
Current lease liabilities	2,830	1,926
Convertible notes payable to related parties, net of discount	6,269	5,624
Total current liabilities	92,651	96,705
Non-current lease liabilities	16,012	12,242
Total liabilities	108,663	108,947
Stockholders’ equity:
Common stock	908	903
Additional paid-in capital	1,594,436	1,568,317
Accumulated other comprehensive income	953	85
Accumulated deficit	(1,272,239)	(1,165,470)
Total stockholders’ equity	324,058	403,835
Total liabilities and stockholders’ equity	$ 432,721	$ 512,782

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues:
Net product sales	$ 22,668	$ 36,659	$ 48,068	$ 68,261
Operating expenses:
Cost of product sales	9,005	13,588	19,627	28,550
Research and development	44,004	41,425	80,898	84,397
General and administrative	9,819	9,778	20,241	19,426
Sales and marketing	15,589	23,647	35,785	52,367
Total operating expenses	78,417	88,438	156,551	184,740
Loss from operations	(55,749)	(51,779)	(108,483)	(116,479)
Other income, net	559	1,557	1,714	3,245
Net loss	(55,190)	(50,222)	(106,769)	(113,234)
Other comprehensive income:
Unrealized gains on short-term investments	245	112	868	235
Comprehensive loss	$ (54,945)	$ (50,110)	$ (105,901)	$ (112,999)
Basic and diluted net loss per share	$ (0.61)	$ (0.63)	$ (1.18)	$ (1.43)
Shares used in computing basic and diluted net loss per share	90,753	79,548	90,581	78,987

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Balance at Dec. 31, 2018	$ 370,160	$ 782	$ 1,330,186	$ (87)	$ (960,721)
Balance (in shares) at Dec. 31, 2018		78,174,000
Conversion benefit included in Convertible Notes issued	102		102
Issuance of common stock on exercise of stock options	6,539	$ 7	6,532
Issuance of common stock on exercise of stock options (in shares)		732,000
Stock-based compensation expense	17,902		17,902
Net loss	(63,012)				(63,012)
Net unrealized gain on short-term investments	123			123
Comprehensive loss	(62,889)
Balance at Mar. 31, 2019	331,814	$ 789	1,354,722	36	(1,023,733)
Balance (in shares) at Mar. 31, 2019		78,906,000
Balance at Dec. 31, 2018	370,160	$ 782	1,330,186	(87)	(960,721)
Balance (in shares) at Dec. 31, 2018		78,174,000
Net loss	(113,234)
Net unrealized gain on short-term investments	235
Comprehensive loss	(112,999)
Balance at Jun. 30, 2019	305,359	$ 798	1,378,368	148	(1,073,955)
Balance (in shares) at Jun. 30, 2019		79,779,000
Balance at Mar. 31, 2019	331,814	$ 789	1,354,722	36	(1,023,733)
Balance (in shares) at Mar. 31, 2019		78,906,000
Conversion benefit included in Convertible Notes issued	103		103
Issuance of common stock on exercise of stock options	9,676	$ 8	9,668
Issuance of common stock on exercise of stock options (in shares)		810,000
Issuance of common stock under the employee stock purchase plan	1,170	$ 1	1,169
Issuance of common stock on under the Employee Stock Purchase Plan (in shares)		63,000
Stock-based compensation expense	12,706		12,706
Net loss	(50,222)				(50,222)
Net unrealized gain on short-term investments	112			112
Comprehensive loss	(50,110)
Balance at Jun. 30, 2019	305,359	$ 798	1,378,368	148	(1,073,955)
Balance (in shares) at Jun. 30, 2019		79,779,000
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
Conversion benefit included in Convertible Notes issued	108		108
Issuance of common stock on exercise of stock options	504		504
Issuance of common stock on exercise of stock options (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 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
Issuance of common stock on exercise of stock options (in shares)	124,000
Net loss	$ (106,769)
Net unrealized gain 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 on exercise of stock options	805	$ 1	804
Issuance of common stock on exercise of stock options (in shares)		54,000
Issuance of common stock 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 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

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating activities:
Net loss	$ (106,769,000)	$ (113,234,000)
Adjustments to reconcile net loss to net cash used for operating activities:
Stock-based compensation expense	23,088,000	30,608,000
Depreciation and amortization	1,366,000	959,000
Amortization of debt discount	645,000	507,000
Realized gain on available-for-sale securities	0	(8,000)
Accretion of discount on short-term investments	(82,000)	(2,437,000)
Impairment of property and equipment	53,000	54,000
Loss on disposal of property and equipment		53,000
Change in operating assets and liabilities:
Accounts receivable	2,377,000	(2,169,000)
Inventory	(16,474,000)	9,762,000
Prepaid expenses and other assets	10,136,000	2,454,000
Accounts payable	15,700,000	(8,866,000)
Accrued clinical and manufacturing liabilities	(4,441,000)	913,000
Accrued payroll and employee liabilities	(4,055,000)	(4,415,000)
Other accrued liabilities	(11,756,000)	13,687,000
Net cash used for operating activities	(90,212,000)	(72,132,000)
Investing activities:
Purchases of short-term investments	(66,915,000)	(204,358,000)
Maturities and sales of short-term investments	166,825,000	284,606,000
Purchases of property and equipment	(3,687,000)	(4,299,000)
Net cash provided by investing activities	96,223,000	75,949,000
Financing activities:
Proceeds from stock option exercises	1,309,000	16,215,000
Proceeds from purchases under the Employee Stock Purchase Plan	1,507,000	1,170,000
Proceeds from warrant exercises	3,000
Net cash provided by financing activities	2,819,000	17,385,000
Net increase in cash and cash equivalents	8,830,000	21,202,000
Cash and cash equivalents at beginning of year	71,898,000	31,836,000
Cash and cash equivalents at end of period	$ 80,728,000	$ 53,038,000

Business

Business	6 Months Ended
	Jun. 30, 2020
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. We are developing novel, patient-focused solutions that apply our innovative science and technologies to already-approved pharmacological agents for patients suffering from pain or cancer. 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”) 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 (“MEC”). 1 1 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. CINVANTI is under investigation for the treatment of Coronavirus Disease 2019 (“COVID-19”) as a daily 2-minute IV injection when added to the current standard of care. HTX-011 (ZYNRELEF in the European Union), an investigational non-opioid, is a dual-acting, fixed-dose combination of the local anesthetic bupivacaine with a low dose of the nonsteroidal anti-inflammatory drug meloxicam. It is the first and only extended-release local anesthetic to demonstrate in Phase 3 studies significantly reduced pain and opioid use through 72 hours compared to bupivacaine solution, the current standard-of-care local anesthetic for postoperative pain control. HTX-011 was granted Fast Track designation from the FDA in the fourth quarter of 2017 and Breakthrough Therapy designation in the second quarter of 2018. Heron submitted a New Drug Application (“NDA”) to the FDA for HTX-011 in October 2018 and received Priority Review designation in December 2018. A Complete Response Letter (“CRL”) was received from the FDA regarding the NDA for HTX-011 on June 26, 2020. The CRL stated that the FDA is unable to approve the NDA in its present form based on the need for additional non-clinical information. Based on the complete review of the NDA, the FDA did not identify any clinical safety or efficacy issues or chemistry, manufacturing and controls issues. There are four non-clinical issues in the CRL, none of which relate to any observed toxicity. Three relate to confirming exposure of excipients in preclinical reproductive toxicology studies, and the fourth relates to changing the manufacturing release specification of the allowable level of an impurity based on animal toxicology coverage. The European Medicines Agency’s Committee for Medicinal Products for Human Use (“CHMP”) adopted a positive opinion for ZYNRELEF in July 2020. The CHMP’s positive opinion will now be reviewed by the European Commission (“EC”), with a final decision on the Marketing Authorisation Application expected in the coming months. An EC marketing authorisation through the Centralised Procedure is valid in all 27 European Union member countries as well as the European Economic Area countries. The CHMP recommended that ZYNRELEF be indicated for treatment of somatic postoperative pain from small- to medium-sized surgical wounds in adults. Heron’s New Drug Submission for HTX-011 for the management of postoperative pain was granted Priority Review status by Health Canada in October 2019 and accepted by Health Canada in November 2019. Heron is working to respond to a list of questions received from Health Canada in July 2020. 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 HTX-011 (ZYNRELEF in the European Union) . 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. The study initiation follows clearance from the FDA of our Investigational New Drug application for HTX-034 for the treatment of postoperative pain. As of June 30, 2020 we had $300.8 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

Basis of Presentation	6 Months Ended
	Jun. 30, 2020
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, 2020 are not necessarily indicative of the results that may be expected for other quarters or the year ending December 31, 2020. The condensed consolidated balance sheet as of December 31, 2019 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, 2019, which was filed with the SEC on March 2, 2020.

Accounting Policies

Accounting Policies	6 Months Ended
	Jun. 30, 2020
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), 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. Our bank and investment accounts have been placed under a control agreement in accordance with our Senior Secured Convertible Notes (“Convertible Notes”) (see Note 8). 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. Our products are distributed in the U.S. through a limited number of specialty distributors and full line wholesalers (collectively, “Customers”) that resell our products to healthcare providers and hospitals, the end users. 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, 2020 Six Months Ended June 30, 2020 As of June 30, 2020 Customer A 44.5 % 42.5 % 56.1 % Customer B 32.2 % 34.5 % 32.2 % Customer C 21.3 % 21.1 % 10.9 % Total 98.0 % 98.1 % 99.2 % Accounts Receivable, Net Accounts receivable are recorded at the invoice amount, net of an allowance for doubtful accounts. The allowance for doubtful accounts reflects accounts receivable balances that are believed to be uncollectible. In estimating the allowance for doubtful accounts, 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; and (3) the outstanding balances and past due amounts from our Customers. As of June 30, 2020 and December 31, 2019, we determined that an allowance for doubtful accounts was not required. For the three and six months ended June 30, 2020 and 2019, 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 In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-02, Leases (Topic 842) Leases (Topic 842): Targeted Improvements Codification Improvements to Topic 842, Leases Leases We determine if an agreement is a lease or contains lease components at inception. Operating leases are recorded as lease liabilities with corresponding ROU lease assets on the condense d consolidated balance sheets. RO U lease asse ts represent our right to use the underlying asset s 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 asset s 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 include s any option to extend or terminate the lease when it is reasonably certain that we will exercise that option. L ease 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 FASB issued ASU No. 2014-09, Revenue from Contracts with Customers Product Sales CINVANTI is distributed in the U.S. through a limited number of Customers that resell CINVANTI to healthcare providers and hospitals, the end users of CINVANTI. SUSTOL is distributed in the U.S. through a limited number of Customers that resell SUSTOL to healthcare providers, the end users of 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 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 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, 2020 were $22.7 million and $48.1 million, respectively, compared to $36.7 million and $68.3 million, respectively, for the same periods in 2019. For the three and six months ended June 30, 2020, net products sales of CINVANTI were $22.6 million and $47.8 million, respectively, compared to $33.2 million and $61.2 million, respectively, for the same periods in 2019. For the three and six months ended June 30, 2020, net product sales of SUSTOL were $0.1 million and $0.3 million, respectively, compared to $3.5 million and $7.1 million, respectively, for the same periods in 2019. 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, 2019 $ 2,351 $ 3,999 $ 21,589 $ 27,939 Provision 382 8,215 50,100 58,697 Payments/credits (100 ) (8,843 ) (58,583 ) (67,526 ) Balance at June 30, 2020 $ 2,633 $ 3,371 $ 13,106 $ 19,110 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 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, 2020 2019 Stock options outstanding 16,306 13,545 Warrants outstanding 220 640 Shares of common stock underlying Convertible Notes outstanding 9,231 8,729 Recent Accounting Pronouncements Adopted in 2020 In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments Financial Instruments - Credit Losses (Topic 326): Targeted Transition Relief have a material impact on our results of operations, financial condition or internal controls. Not Yet Adopted In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740)

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2020
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 ASC Topic 820, Fair Value Measurements and Disclosures • 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, 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 $ 73,104 $ 73,104 $ — $ — U.S. treasury bills and government agency obligations 100,869 100,869 — — U.S. corporate debt securities 52,716 — 52,716 — Foreign corporate debt securities 23,736 — 23,736 — U.S. commercial paper 18,968 — 18,968 — Foreign commercial paper 31,449 — 31,449 — Total $ 300,842 $ 173,973 $ 126,869 $ — Fair Value Measurements at Reporting Date Using Balance at December 31, 2019 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 $ 56,931 $ 56,931 $ — $ — U.S. treasury bills and government agency obligations 140,626 140,626 — — U.S. corporate debt securities 80,170 — 80,170 — Foreign corporate debt securities 23,203 — 23,203 — U.S. commercial paper 32,801 — 32,801 — Foreign commercial paper 57,241 — 57,241 — Total $ 390,972 $ 197,557 $ 193,415 $ — We have not transferred any investment securities between the three levels of the fair value hierarchy. As of June 30, 2020, cash equivalents included $7.6 million of available-for-sale securities with contractual maturities of three months or less. As of June 30, 2020, short-term investments included $205.7 million of available-for-sale securities with contractual maturities of three months to one year and $14.4 million of available-for-sale securities with contractual maturities greater than one year. As of December 31, 2019, cash equivalents included $15.0 million of available-for-sale securities with contractual maturities of three months or less. As of December 31, 2019, short-term investments included $279.7 million of available-for-sale securities with contractual maturities of three months to one year and $39.4 million of available-for-sale securities with contractual maturities greater than one year. The money market funds as of June 30, 2020 and December 31, 2019 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, 2020 do not have a readily available market value, however, the carrying value is considered to approximate its fair value.

Short-term Investments

Short-term Investments	6 Months Ended
	Jun. 30, 2020
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, 2020 Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value U.S. treasury bills and government agency obligations $ 100,309 $ 560 $ — $ 100,869 U.S. corporate debt securities 44,861 231 — 45,092 Foreign corporate debt securities 23,574 162 — 23,736 U.S. commercial paper 18,968 — — 18,968 Foreign commercial paper 31,449 — — 31,449 Total $ 219,161 $ 953 $ — $ 220,114 December 31, 2019 Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value U.S. treasury bills and government agency obligations $ 140,567 $ 59 $ — $ 140,626 U.S. corporate debt securities 80,159 11 — 80,170 Foreign corporate debt securities 23,188 15 — 23,203 U.S. commercial paper 32,801 — — 32,801 Foreign commercial paper 42,274 — — 42,274 Total $ 318,989 $ 85 $ — $ 319,074 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, 2020 and 2019. 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 months ended June 30, 2020 and 2019. We did not recognize any realized gains or losses during the six months ended June 30, 2020. We recognized $8,000 of realized gains during the six months ended June 30, 2019.

Inventory

Inventory	6 Months Ended
	Jun. 30, 2020
Inventory Disclosure [Abstract]
Inventory	6. Inventory Inventory consists of the following (in thousands): June 30, 2020 December 31, 2019 Raw materials $ 18,979 $ 6,635 Work in process 12,820 12,571 Finished goods 9,643 5,762 Total inventory $ 41,442 $ 24,968 As of June 30, 2020, total inventory included $39.7 million related to CINVANTI and $1.7 million related to SUSTOL. As of December 31, 2019, total inventory included $23.5 million related to CINVANTI and $1.5 million related to SUSTOL. In addition, cost of product sales for the six months ended June 30, 2019 included charges of $1.6 million resulting from the write-off of short-dated SUSTOL inventory.

Leases

Leases	6 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Leases	7. Leases In December 2019, we amended our existing operating lease for laboratory and office space in San Diego, California to expand the office space by an additional 21,180 square feet (“Lease Amendment”). The Lease Amendment commenced on January 1, 2020 and expires on December 31, 2025. We have an option to extend the lease for an additional 5 years on expiration. As of June 30, 2020, our operating lease for laboratory and office space in San Diego, California had a remaining lease term of 66 months. On January 1, 2019, on the adoption of Topic 842, we recognized initial ROU lease assets of $13.7 million and initial lease liabilities of $14.5 million. The option to extend our operating lease in San Diego was not recognized as part of our lease liability and ROU lease assets. During the three and six months ended June 30, 2020, we recognized $1.0 million and $2.0 million, respectively, of operating lease expense and we paid $1.0 million and $1.7 million, respectively, for our operating leases. Future minimum lease payments under our operating leases as of June 30, 2020 are as follows (in thousands): 2020 $ 1,922 2021 3,942 2022 4,058 2023 4,178 2024 4,274 Thereafter 4,379 Total future minimum lease payments $ 22,753 Less: discount (3,911 ) Total lease liabilities $ 18,842

Secured Notes to Related Party

Secured Notes to Related Party	6 Months Ended
	Jun. 30, 2020
Debt Disclosure [Abstract]
Secured Notes to Related Party	8. Secured Notes to Related Party 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 and currently serves as the Chairman of our Board of Directors. 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 are secured by substantially all of our assets, including placing our bank and investment accounts under a control agreement. The Convertible Notes bear 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 mature on May 2, 2021; however, the holders of the Convertible Notes may require prepayment of the Convertible Notes at any time, at each holder’s option. The Convertible Notes are convertible into shares of our common stock at a rate of 1,250 shares for every $1,000 of outstanding principal due under the Convertible Notes. There is no right to convert the Convertible Notes to the extent that, after giving effect to such conversion, the holder would beneficially own in excess of 9.99% of our outstanding common stock. Each holder of the Convertible Notes can increase or decrease this beneficial ownership conversion limit by written notice to us, which will not be effective until 61 days after delivery of the notice. As of June 30, 2020, we were in compliance with all covenants under the Convertible Notes. On the occurrence of an event of default under the Convertible Notes, the holders of the Convertible Notes have the right to require us to redeem all or a portion of their Convertible Notes. 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 and to register the additional shares underlying the Convertible Notes until they provide notice otherwise. 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 six months ended June 30, 2020, 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 months ended June 30, 2020 and 2019, interest expense relating to the stated rate was $0.1 million. For each of the three months ended June 30, 2020 and 2019, interest expense relating to the amortization of the debt discount was $0.3 million. For each of the six months ended June 30, 2020 and 2019, interest expense relating to the stated rate was $0.2 million. For the six months ended June 30, 2020 and 2019, interest expense relating to the amortization of the debt discount was $0.6 million and $0.5 million, respectively. As of June 30, 2020, the carrying value of the Convertible Notes was $6.3 million, which is comprised of the $7.4 million principal amount of the Convertible Notes outstanding, less debt discount of $1.1 million. As of June 30, 2020, the Convertible Notes were convertible into 9.2 million shares of our common stock.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Stockholders' Equity	9. Stockholders’ Equity 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 six months ended June 30, 2020, warrant holders exercised 267,870 warrants, which resulted in the issuance of 267,870 shares for net cash proceeds of $2,679. As of June 30, 2020, 195,574 warrants from the June 2014 public offering remain outstanding. Stock Option Activity The following table summarizes the stock option activity for the six months ended June 30, 2020: Shares (in thousands) Weighted- average Exercise Price Weighted- average Remaining Contractual Term (Years) Balance at December 31, 2019 16,665 $ 20.47 7.87 Granted 249 $ 19.24 Exercised (124 ) $ 10.57 Expired and forfeited (484 ) $ 22.57 Balance at June 30, 2020 16,306 $ 20.46 7.31 For the six months ended June 30, 2020, 124,000 shares of common stock were issued pursuant to the exercise of stock options, resulting in net proceeds of $1.3 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, 2020 2019 2020 2019 Research and development $ 4,681 $ 4,434 $ 9,968 $ 9,758 General and administrative 3,304 3,714 6,735 7,394 Sales and marketing 3,129 4,558 6,385 13,456 Total stock-based compensation expense $ 11,114 $ 12,706 $ 23,088 $ 30,608 As of June 30, 2020, there 103.0 2.7 . 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, 2020 2019 Risk-free interest rate 1.1 % 2.4 % Dividend yield 0.0 % 0.0 % Volatility 66.7 % 68.0 % 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, 2020 2019 Risk-free interest rate 0.1 % 2.4 % Dividend yield 0.0 % 0.0 % Volatility 63.3 % 58.4 % Expected life (months) 6 6

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	10. 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, 2020. 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, 2019, which was filed with the SEC on March 2, 2020, continue to be accurate for the three and six months ended June 30, 2020.

Accounting Policies (Policies)

Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
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, 2020 are not necessarily indicative of the results that may be expected for other quarters or the year ending December 31, 2020. The condensed consolidated balance sheet as of December 31, 2019 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, 2019, which was filed with the SEC on March 2, 2020.
Principles of Consolidation	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	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, 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), 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. Our bank and investment accounts have been placed under a control agreement in accordance with our Senior Secured Convertible Notes (“Convertible Notes”) (see Note 8).
Concentration of Credit Risk	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. Our products are distributed in the U.S. through a limited number of specialty distributors and full line wholesalers (collectively, “Customers”) that resell our products to healthcare providers and hospitals, the end users. 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, 2020 Six Months Ended June 30, 2020 As of June 30, 2020 Customer A 44.5 % 42.5 % 56.1 % Customer B 32.2 % 34.5 % 32.2 % Customer C 21.3 % 21.1 % 10.9 % Total 98.0 % 98.1 % 99.2 %
Accounts Receivable, Net	Accounts Receivable, Net Accounts receivable are recorded at the invoice amount, net of an allowance for doubtful accounts. The allowance for doubtful accounts reflects accounts receivable balances that are believed to be uncollectible. In estimating the allowance for doubtful accounts, 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; and (3) the outstanding balances and past due amounts from our Customers. As of June 30, 2020 and December 31, 2019, we determined that an allowance for doubtful accounts was not required. For the three and six months ended June 30, 2020 and 2019, we did not write off any accounts receivable balances.
Inventory	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	Leases In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-02, Leases (Topic 842) Leases (Topic 842): Targeted Improvements Codification Improvements to Topic 842, Leases Leases We determine if an agreement is a lease or contains lease components at inception. Operating leases are recorded as lease liabilities with corresponding ROU lease assets on the condense d consolidated balance sheets. RO U lease asse ts represent our right to use the underlying asset s 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 asset s 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 include s any option to extend or terminate the lease when it is reasonably certain that we will exercise that option. L ease 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 Recognition In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers Product Sales CINVANTI is distributed in the U.S. through a limited number of Customers that resell CINVANTI to healthcare providers and hospitals, the end users of CINVANTI. SUSTOL is distributed in the U.S. through a limited number of Customers that resell SUSTOL to healthcare providers, the end users of 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 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 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, 2020 were $22.7 million and $48.1 million, respectively, compared to $36.7 million and $68.3 million, respectively, for the same periods in 2019. For the three and six months ended June 30, 2020, net products sales of CINVANTI were $22.6 million and $47.8 million, respectively, compared to $33.2 million and $61.2 million, respectively, for the same periods in 2019. For the three and six months ended June 30, 2020, net product sales of SUSTOL were $0.1 million and $0.3 million, respectively, compared to $3.5 million and $7.1 million, respectively, for the same periods in 2019. 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, 2019 $ 2,351 $ 3,999 $ 21,589 $ 27,939 Provision 382 8,215 50,100 58,697 Payments/credits (100 ) (8,843 ) (58,583 ) (67,526 ) Balance at June 30, 2020 $ 2,633 $ 3,371 $ 13,106 $ 19,110
Comprehensive Loss	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 and represent the difference between our net loss and comprehensive loss for all periods presented.
Net Loss per Share	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, 2020 2019 Stock options outstanding 16,306 13,545 Warrants outstanding 220 640 Shares of common stock underlying Convertible Notes outstanding 9,231 8,729
Recent Accounting Pronouncements	Recent Accounting Pronouncements Adopted in 2020 In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments Financial Instruments - Credit Losses (Topic 326): Targeted Transition Relief have a material impact on our results of operations, financial condition or internal controls. Not Yet Adopted In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740)

Accounting Policies (Tables)

Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Percentage of Net Product Sales and Accounts Receivable Balance	Our products are distributed in the U.S. through a limited number of specialty distributors and full line wholesalers (collectively, “Customers”) that resell our products to healthcare providers and hospitals, the end users. 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, 2020 Six Months Ended June 30, 2020 As of June 30, 2020 Customer A 44.5 % 42.5 % 56.1 % Customer B 32.2 % 34.5 % 32.2 % Customer C 21.3 % 21.1 % 10.9 % Total 98.0 % 98.1 % 99.2 %
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 condensed consolidated balance sheets (in thousands): Product Returns Distributor Fees Discounts, Rebates and Administrative Fees Total Balance at December 31, 2019 $ 2,351 $ 3,999 $ 21,589 $ 27,939 Provision 382 8,215 50,100 58,697 Payments/credits (100 ) (8,843 ) (58,583 ) (67,526 ) Balance at June 30, 2020 $ 2,633 $ 3,371 $ 13,106 $ 19,110
Common Stock Equivalents Excluded From Computation of Net Loss Per Share	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, 2020 2019 Stock options outstanding 16,306 13,545 Warrants outstanding 220 640 Shares of common stock underlying Convertible Notes outstanding 9,231 8,729

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2020
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, 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 $ 73,104 $ 73,104 $ — $ — U.S. treasury bills and government agency obligations 100,869 100,869 — — U.S. corporate debt securities 52,716 — 52,716 — Foreign corporate debt securities 23,736 — 23,736 — U.S. commercial paper 18,968 — 18,968 — Foreign commercial paper 31,449 — 31,449 — Total $ 300,842 $ 173,973 $ 126,869 $ — Fair Value Measurements at Reporting Date Using Balance at December 31, 2019 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 $ 56,931 $ 56,931 $ — $ — U.S. treasury bills and government agency obligations 140,626 140,626 — — U.S. corporate debt securities 80,170 — 80,170 — Foreign corporate debt securities 23,203 — 23,203 — U.S. commercial paper 32,801 — 32,801 — Foreign commercial paper 57,241 — 57,241 — Total $ 390,972 $ 197,557 $ 193,415 $ —

Short-term Investments (Tables)

Short-term Investments (Tables)	6 Months Ended
	Jun. 30, 2020
Short Term Investments [Abstract]
Summary of Short-term Investments	The following is a summary of our short-term investments (in thousands): June 30, 2020 Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value U.S. treasury bills and government agency obligations $ 100,309 $ 560 $ — $ 100,869 U.S. corporate debt securities 44,861 231 — 45,092 Foreign corporate debt securities 23,574 162 — 23,736 U.S. commercial paper 18,968 — — 18,968 Foreign commercial paper 31,449 — — 31,449 Total $ 219,161 $ 953 $ — $ 220,114 December 31, 2019 Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value U.S. treasury bills and government agency obligations $ 140,567 $ 59 $ — $ 140,626 U.S. corporate debt securities 80,159 11 — 80,170 Foreign corporate debt securities 23,188 15 — 23,203 U.S. commercial paper 32,801 — — 32,801 Foreign commercial paper 42,274 — — 42,274 Total $ 318,989 $ 85 $ — $ 319,074

Inventory (Tables)

Inventory (Tables)	6 Months Ended
	Jun. 30, 2020
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventory consists of the following (in thousands): June 30, 2020 December 31, 2019 Raw materials $ 18,979 $ 6,635 Work in process 12,820 12,571 Finished goods 9,643 5,762 Total inventory $ 41,442 $ 24,968

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Summary of Future Minimum Lease Payments	Future minimum lease payments under our operating leases as of June 30, 2020 are as follows (in thousands): 2020 $ 1,922 2021 3,942 2022 4,058 2023 4,178 2024 4,274 Thereafter 4,379 Total future minimum lease payments $ 22,753 Less: discount (3,911 ) Total lease liabilities $ 18,842

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Stock Option Activity	The following table summarizes the stock option activity for the six months ended June 30, 2020: Shares (in thousands) Weighted- average Exercise Price Weighted- average Remaining Contractual Term (Years) Balance at December 31, 2019 16,665 $ 20.47 7.87 Granted 249 $ 19.24 Exercised (124 ) $ 10.57 Expired and forfeited (484 ) $ 22.57 Balance at June 30, 2020 16,306 $ 20.46 7.31
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, 2020 2019 2020 2019 Research and development $ 4,681 $ 4,434 $ 9,968 $ 9,758 General and administrative 3,304 3,714 6,735 7,394 Sales and marketing 3,129 4,558 6,385 13,456 Total stock-based compensation expense $ 11,114 $ 12,706 $ 23,088 $ 30,608
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, 2020 2019 Risk-free interest rate 1.1 % 2.4 % Dividend yield 0.0 % 0.0 % Volatility 66.7 % 68.0 % Expected life (years) 6 6
1997 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Fair Value of Option Grant on Grant Date Using Black-Scholes Option Pricing Model	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, 2020 2019 Risk-free interest rate 0.1 % 2.4 % Dividend yield 0.0 % 0.0 % Volatility 63.3 % 58.4 % Expected life (months) 6 6

Business - Additional Informati

Business - Additional Information (Details) $ in Millions	Jun. 30, 2020USD ($)
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Cash, cash equivalents and short-term investments	$ 300.8

Accounting Policies - Percentag

Accounting Policies - Percentage of Net Product Sales and Accounts Receivable Balance (Details) - Customer Concentration Risk	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
Revenue Benchmark
Product Information [Line Items]
Concentration risk percentage	98.00%	98.10%
Revenue Benchmark | Largest Customer
Product Information [Line Items]
Concentration risk percentage	44.50%	42.50%
Revenue Benchmark | Second Largest Customer
Product Information [Line Items]
Concentration risk percentage	32.20%	34.50%
Revenue Benchmark | Third Largest Customer
Product Information [Line Items]
Concentration risk percentage	21.30%	21.10%
Accounts Receivable
Product Information [Line Items]
Concentration risk percentage		99.20%
Accounts Receivable | Largest Customer
Product Information [Line Items]
Concentration risk percentage		56.10%
Accounts Receivable | Second Largest Customer
Product Information [Line Items]
Concentration risk percentage		32.20%
Accounts Receivable | Third Largest Customer
Product Information [Line Items]
Concentration risk percentage		10.90%

Accounting Policies - Additiona

Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Product Information [Line Items]
Net product sales	$ 22,668	$ 36,659	$ 48,068	$ 68,261
CINVANTI
Product Information [Line Items]
Net product sales	22,600	33,200	47,800	61,200
SUSTOL
Product Information [Line Items]
Net product sales	$ 100	$ 3,500	$ 300	$ 7,100

Accounting Policies - Summary o

Accounting Policies - Summary of Activity to Product Returns, Distributor Fees and Discounts, Rebates and Administrative Fees (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)
Product Information [Line Items]
Balance	$ 27,939
Provision	58,697
Payments/credits	(67,526)
Balance	19,110
Product Returns
Product Information [Line Items]
Balance	2,351
Provision	382
Payments/credits	(100)
Balance	2,633
Distributor Fees
Product Information [Line Items]
Balance	3,999
Provision	8,215
Payments/credits	(8,843)
Balance	3,371
Discounts, Rebates and Administrative Fees
Product Information [Line Items]
Balance	21,589
Provision	50,100
Payments/credits	(58,583)
Balance	$ 13,106

Accounting Policies - Common St

Accounting Policies - Common Stock Equivalents Excluded From Computation of Net Loss Per Share (Details) - shares shares in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Share-based Payment Arrangement, Option
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded (in shares)	16,306	13,545
Warrant
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded (in shares)	220	640
Convertible Debt Securities
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded (in shares)	9,231	8,729

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 220,114	$ 319,074
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	100,869	140,626
U.S. Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	45,092	80,170
Foreign Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	23,736	23,203
U.S. Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	18,968	32,801
Fair Value, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	300,842	390,972
Fair Value, Recurring | Foreign Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	31,449	57,241
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	100,869	140,626
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	52,716	80,170
Fair Value, Recurring | Foreign Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	23,736	23,203
Fair Value, Recurring | U.S. Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities	18,968	32,801
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	173,973	197,557
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	100,869	140,626
Fair Value, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	126,869	193,415
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	31,449	57,241
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	52,716	80,170
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	23,736	23,203
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	18,968	32,801
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	73,104	56,931
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	$ 73,104	$ 56,931

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Financial instruments transferred among fair value hierarchy levels	$ 0
Cash equivalents included of available-for-sale securities	7,600,000	$ 15,000,000
Available for sale securities with contractual maturities of three months to one year.	205,700,000	279,700,000
Available for sale securities with contractual maturities greater than one year	$ 14,400,000	$ 39,400,000

Short-term Investments - Summar

Short-term Investments - Summary of Short-term Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	$ 219,161	$ 318,989
Available-for-sale securities, gross unrealized gains	953	85
Available-for-sale securities	220,114	319,074
U.S. Treasury Bills and Government Agency Obligations
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	100,309	140,567
Available-for-sale securities, gross unrealized gains	560	59
Available-for-sale securities	100,869	140,626
U.S. Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	44,861	80,159
Available-for-sale securities, gross unrealized gains	231	11
Available-for-sale securities	45,092	80,170
Foreign Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	23,574	23,188
Available-for-sale securities, gross unrealized gains	162	15
Available-for-sale securities	23,736	23,203
U.S. Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	18,968	32,801
Available-for-sale securities	18,968	32,801
Foreign Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, amortized cost	31,449	42,274
Available-for-sale securities	$ 31,449	$ 42,274

Short-term Investments - Additi

Short-term Investments - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Short Term Investments [Abstract]
Debt securities, impairment losses	$ 0	$ 0	$ 0	$ 0
Debt securities, available-for-sale, realized gain (loss)	$ 0	$ 0	$ 0	$ 8,000

Inventory - Schedule of Invento

Inventory - Schedule of Inventory (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 18,979	$ 6,635
Work in process	12,820	12,571
Finished goods	9,643	5,762
Total inventory	$ 41,442	$ 24,968

Inventory - Additional Informat

Inventory - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2020	Dec. 31, 2019
Inventory [Line Items]
Total inventory		$ 41,442	$ 24,968
CINVANTI
Inventory [Line Items]
Total inventory		39,700	23,500
SUSTOL
Inventory [Line Items]
Total inventory		$ 1,700	$ 1,500
Cost of product sales, charges	$ 1,600

Leases - Additional Information

Leases - Additional Information (Details) $ in Thousands	1 Months Ended	3 Months Ended	6 Months Ended
	Dec. 31, 2019USD ($)ft²	Jun. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Jan. 01, 2019USD ($)
Lessee Lease Description [Line Items]
Right-of-use lease assets	$ 13,754	$ 17,594	$ 17,594
Operating lease, initial lease liabilities		18,842	18,842
Operating lease, expense		1,000	2,000
Operating lease, payments		$ 1,000	$ 1,700
Accounting Standards Update 2016-02
Lessee Lease Description [Line Items]
Right-of-use lease assets				$ 13,700
Operating lease, initial lease liabilities				$ 14,500
San Diego, California
Lessee Lease Description [Line Items]
Area of real estate property | ft²	21,180
Lease commencement date	Jan. 1, 2020
Lease expiration date	Dec. 31, 2025
Lessee, operating lease, renewal term	5 years
Lessee, operating lease, existence of option to extend	true
Operating leases, remaining lease term		66 months	66 months

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Lease Payments (Details) $ in Thousands	Jun. 30, 2020USD ($)
Leases [Abstract]
2020	$ 1,922
2021	3,942
2022	4,058
2023	4,178
2024	4,274
Thereafter	4,379
Total future minimum lease payments	22,753
Less: discount	(3,911)
Total lease liabilities	$ 18,842

Secured Notes to Related Party

Secured Notes to Related Party - Additional Information (Details)	Jul. 29, 2011shares	Apr. 30, 2011USD ($)Dayshares	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2020USD ($)shares	Jun. 30, 2019USD ($)
Debt Instrument [Line Items]
Proceeds from convertible debt		$ 4,300,000
Amortization of debt discount					$ 645,000	$ 507,000
Debt instrument, convertible, number shares of equity instruments | shares					9,200,000
Convertible Notes
Debt Instrument [Line Items]
Convertible debt issuable in connection with private placement		$ 4,500,000
Debt instrument, interest rate		6.00%
Debt instrument, maturity date		May 2, 2021
Debt instrument conversion ratio multiple of principal		$ 1,000
Beneficial ownership after conversion		9.99%
Notice period associated with beneficial ownership percentage limitation convertible notes | Day		61
Common shares registered for resale in connection with convertible notes | shares	3,500,000
Debt instrument, term		10 years
Paid-in-kind interest					$ 200,000
Debt instrument, additional debt discount					200,000
Interest expense, debt, excluding amortization			$ 100,000	$ 100,000	200,000	200,000
Amortization of debt discount			300,000	$ 300,000	600,000	$ 500,000
Carrying value of debt			6,300,000		6,300,000
Debt instrument, face amount			7,400,000		7,400,000
Debt instrument, unamortized discount, total			$ 1,100,000		$ 1,100,000
Convertible Notes | Common Stock
Debt Instrument [Line Items]
Debt instrument, number of shares issued for convertible notes | shares		1,250

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended				6 Months Ended
	Oct. 31, 2019	Jun. 30, 2014	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Class Of Stock [Line Items]
Proceeds from issuance of common stock	$ 162,200,000
Shares of common stock issued pursuant to exercise of stock options							124,000
Proceeds from stock option exercises							$ 1,309,000	$ 16,215,000
Total unrecognized compensation cost related to non-vested, stock-based payment awards			$ 103,000,000				$ 103,000,000
Total unrecognized compensation cost, expect to recognize over weighted average period							2 years 8 months 12 days
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							267,870
Proceeds from issuance of warrants							$ 2,679
Class of warrant or right, outstanding			195,574				195,574
Common Stock
Class Of Stock [Line Items]
Number of shares issued	9,900,000
Share price	$ 17.50
Payments of stock issuance costs	$ 10,300,000
Issuance of common stock on exercise of warrants (in shares)				268,000
Shares of common stock issued pursuant to exercise of stock options			54,000	70,000	810,000	732,000
Common Stock | Pre-funded Warrants
Class Of Stock [Line Items]
Issuance of common stock on exercise of warrants (in shares)							267,870

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Option Activity (Details) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Equity [Abstract]
Number of shares outstanding	16,665,000
Number of shares granted	249,000
Number of shares exercised	(124,000)
Number of shares expired and forfeited	(484,000)
Number of shares outstanding	16,306,000	16,665,000
Number of shares outstanding, weighted average exercise price	$ 20.47
Number of shares granted, weighted average exercise price	19.24
Number of shares exercised, weighted average exercise price	10.57
Number of shares expired and forfeited, weighted average exercise price	22.57
Number of shares outstanding, weighted average exercise price	$ 20.46	$ 20.47
Number of shares outstanding, weighted average remaining contractual term (Year)	7 years 3 months 21 days	7 years 10 months 13 days

Stockholders' Equity - Summar_2

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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 11,114	$ 12,706	$ 23,088	$ 30,608
Research and Development Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	4,681	4,434	9,968	9,758
General and Administrative Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	3,304	3,714	6,735	7,394
Selling and Marketing Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 3,129	$ 4,558	$ 6,385	$ 13,456

Stockholders' Equity - Summar_3

Stockholders' Equity - Summary of Fair Value of Option Grant on Grant Date Using Black-Scholes Option Pricing Model (Details)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Share-based Payment Arrangement, Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	1.10%	2.40%
Dividend yield	0.00%	0.00%
Volatility	66.70%	68.00%
Expected life	6 years	6 years
1997 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	0.10%	2.40%
Dividend yield	0.00%	0.00%
Volatility	63.30%	58.40%
Expected life	6 months	6 months