Ocular Therapeutix (OCUL) 10-Q 9 Aug 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 04, 2021
Document And Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Entity File Number	001-36554
Entity Registrant Name	Ocular Therapeutix, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-5560161
Entity Address, Address Line One	24 Crosby Drive
Entity Address, City or Town	Bedford
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01730
City Area Code	781
Local Phone Number	357-4000
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	OCUL
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		76,582,927
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001393434
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 191,860	$ 228,057
Accounts receivable, net	18,734	12,252
Inventory	1,112	1,201
Prepaid expenses and other current assets	4,817	4,650
Total current assets	216,523	246,160
Property and equipment, net	7,042	8,095
Restricted cash	1,764	1,764
Operating lease assets	5,378	5,844
Total assets	230,707	261,863
Current liabilities:
Accounts payable	3,881	2,709
Accrued expenses and other current liabilities	16,182	14,307
Operating lease liabilities	1,487	1,358
Notes payable, net of discount, current		8,290
Total current liabilities	21,550	26,664
Operating lease liabilities, net of current portion	6,770	7,548
Derivative liability	59,901	98,313
Deferred revenue	12,000	12,000
Notes payable, net of discount	24,891	16,936
2026 convertible notes, net	25,348	24,307
Total liabilities	150,460	185,768
Commitments and contingencies (Note 14)
Stockholders' equity:
Preferred stock, $0.0001 par value; 5,000,000 shares authorized and no shares issued or outstanding at June 30, 2021 and December 31, 2020, respectively
Common stock, $0.0001 par value; 200,000,000 shares authorized and 76,454,597 and 75,996,732 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively	8	8
Additional paid-in capital	624,850	615,338
Accumulated deficit	(544,611)	(539,251)
Total stockholders' equity	80,247	76,095
Total liabilities and stockholders' equity	$ 230,707	$ 261,863

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Condensed Consolidated Balance Sheets
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	76,454,597	75,996,732
Common stock, shares outstanding	76,454,597	75,996,732

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue:
Product revenue, net	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Total revenue, net	$ 11,718	$ 1,569	$ 19,061	$ 4,178
Costs and operating expenses:
Cost, Product and Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Cost of product revenue	$ 1,096	$ 134	$ 1,988	$ 953
Research and development	13,859	8,021	24,786	14,119
Selling and marketing	8,391	6,153	16,477	13,283
General and administrative	8,603	5,145	16,268	10,321
Total costs and operating expenses	31,949	19,453	59,519	38,676
Loss from operations	(20,231)	(17,884)	(40,458)	(34,498)
Other income (expense):
Interest income	8	17	20	156
Interest expense	(1,655)	(1,694)	(3,335)	(3,327)
Change in fair value of derivative liability	13,396	(17,007)	38,412	(20,411)
Other income (expense), net	1		1
Total other income (expense), net	11,750	(18,684)	35,098	(23,582)
Net loss	$ (8,481)	$ (36,568)	$ (5,360)	$ (58,080)
Net loss per share - basic	$ (0.11)	$ (0.64)	$ (0.07)	$ (1.06)
Weighted average common shares outstanding, basic	76,324,367	57,368,292	76,198,384	54,634,572
Net loss per share - diluted	$ (0.25)	$ (0.64)	$ (0.51)	$ (1.06)
Weighted average common shares outstanding, diluted	82,093,599	57,368,292	81,967,616	54,634,572

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net loss	$ (5,360)	$ (58,080)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation expense	7,378	3,491
Non-cash interest expense	2,282	2,156
Change in fair value of derivative liability	(38,412)	20,411
Depreciation and amortization expense	1,257	1,441
Changes in operating assets and liabilities:
Accounts receivable	(6,482)	(326)
Prepaid expenses and other current assets	(167)	173
Inventory	89	(113)
Operating lease assets	466	386
Accounts payable	1,255	(786)
Accrued expenses	928	(1,866)
Operating lease liabilities	(649)	(537)
Net cash used in operating activities	(37,415)	(33,650)
Cash flows from investing activities:
Purchases of property and equipment	(287)	(374)
Net cash used in investing activities	(287)	(374)
Cash flows from financing activities:
Proceeds from issuance of notes payable, net	3,722
Proceeds from exercise of stock options	1,735	506
Proceeds from issuance of common stock pursuant to employee stock purchase plan	490	350
Proceeds from the Paycheck Protection Program Loan		3,201
Repayment of the Paycheck Protection Program Loan		(3,201)
Proceeds from issuance of common stock upon public offering, net of issuance costs	(275)	63,025
Repayment of notes payable	(4,167)
Net cash provided by financing activities	1,505	63,881
Net (decrease) increase in cash, cash equivalents and restricted cash	(36,197)	29,857
Cash, cash equivalents and restricted cash at beginning of period	229,821	56,201
Cash, cash equivalents and restricted cash at end of period	193,624	86,058
Supplemental disclosure of non-cash investing and financing activities:
Additions to property and equipment included in accounts payable and accrued expenses at balance sheet dates	$ 8	63
Public offering costs included in accounts payable and accrued expenses at balance sheet dates		$ 318

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Total
Balance at Dec. 31, 2019	$ 5	$ 379,980	$ (383,615)	$ (3,630)
Balance, shares at Dec. 31, 2019	50,333,559
Stockholders' Equity (Deficit)
Issuance of common stock upon exercise of stock options		128		128
Issuance of common stock upon exercise of stock options, shares	46,321
Issuance of common stock upon public offering, net of issuance costs		12,690		12,690
Issuance of common stock upon public offering, net of issuance costs, shares	2,657,823
Stock-based compensation expense		1,665		1,665
Net income (loss)			(21,512)	(21,512)
Balance at Mar. 31, 2020	$ 5	394,463	(405,127)	(10,659)
Balance, shares at Mar. 31, 2020	53,037,703
Balance at Dec. 31, 2019	$ 5	379,980	(383,615)	(3,630)
Balance, shares at Dec. 31, 2019	50,333,559
Stockholders' Equity (Deficit)
Net income (loss)				(58,080)
Balance at Jun. 30, 2020	$ 6	447,033	(441,695)	5,344
Balance, shares at Jun. 30, 2020	62,953,793
Balance at Mar. 31, 2020	$ 5	394,463	(405,127)	(10,659)
Balance, shares at Mar. 31, 2020	53,037,703
Stockholders' Equity (Deficit)
Issuance of common stock upon exercise of stock options		378		378
Issuance of common stock upon exercise of stock options, shares	75,862
Issuance of common stock in connection with employee stock purchase plan		350		350
Issuance of common stock in connection with employee stock purchase plan, shares	104,579
Issuance of common stock upon public offering, net of issuance costs	$ 1	50,016		50,017
Issuance of common stock upon public offering, net of issuance costs, shares	9,735,649
Stock-based compensation expense		1,826		1,826
Net income (loss)			(36,568)	(36,568)
Balance at Jun. 30, 2020	$ 6	447,033	(441,695)	5,344
Balance, shares at Jun. 30, 2020	62,953,793
Balance at Dec. 31, 2020	$ 8	615,338	(539,251)	76,095
Balance, shares at Dec. 31, 2020	75,996,732
Stockholders' Equity (Deficit)
Issuance of common stock upon exercise of stock options		1,197		1,197
Issuance of common stock upon exercise of stock options, shares	228,241
Issuance of common stock upon cashless exercise of warrant, shares	11,737
Issuance costs associated with common stock public offering		(91)		(91)
Stock-based compensation expense		3,086		3,086
Net income (loss)			3,121	3,121
Balance at Mar. 31, 2021	$ 8	619,530	(536,130)	83,408
Balance, shares at Mar. 31, 2021	76,236,710
Balance at Dec. 31, 2020	$ 8	615,338	(539,251)	76,095
Balance, shares at Dec. 31, 2020	75,996,732
Stockholders' Equity (Deficit)
Issuance of common stock upon cashless exercise of warrant, shares	11,737
Net income (loss)				(5,360)
Balance at Jun. 30, 2021	$ 8	624,850	(544,611)	80,247
Balance, shares at Jun. 30, 2021	76,454,597
Balance at Mar. 31, 2021	$ 8	619,530	(536,130)	83,408
Balance, shares at Mar. 31, 2021	76,236,710
Stockholders' Equity (Deficit)
Issuance of common stock upon exercise of stock options		538		538
Issuance of common stock upon exercise of stock options, shares	177,256
Issuance of common stock in connection with employee stock purchase plan		490		490
Issuance of common stock in connection with employee stock purchase plan, shares	40,631
Stock-based compensation expense		4,292		4,292
Net income (loss)			(8,481)	(8,481)
Balance at Jun. 30, 2021	$ 8	$ 624,850	$ (544,611)	$ 80,247
Balance, shares at Jun. 30, 2021	76,454,597

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2021
Nature of the Business and Basis of Presentation
Nature of the Business and Basis of Presentation	1. Nature of the Business and Basis of Presentation ​ Ocular Therapeutix, Inc. (the “Company”) was incorporated on September 12, 2006 under the laws of the State of Delaware. The Company is a biopharmaceutical company focused on the formulation, development and commercialization of innovative therapies for diseases and conditions of the eye using its proprietary, bioresorbable hydrogel platform technology. The Company’s product pipeline candidates provide differentiated drug delivery solutions that reduce the complexity and burden of the current standard of care by creating local programmed-release alternatives. Since inception, the Company’s operations have been primarily focused on organizing and staffing the Company, acquiring rights to intellectual property, business planning, raising capital, developing its technology, identifying potential product candidates, undertaking preclinical studies and clinical trials, manufacturing initial quantities of its products and product candidates and building the initial sales and marketing infrastructure for the commercialization of the Company’s approved products and product candidates and launching its initial product. ​ The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations, regulatory approval and compliance, reimbursement, uncertainty of market acceptance of products and the need to obtain additional financing. Recently approved products will require significant sales, marketing and distribution support up to and including upon their launch. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization. ​ As of June 30, 2021, the Company had two FDA-approved products in commercialization in the United States: DEXTENZA ® ® Sealant, an ophthalmic device designed to prevent wound leaks in corneal incisions following cataract surgery. While ReSure Sealant is commercially available in the United States, it does not receive sales support and has not in the past generated, nor is it anticipated to in the future to generate, material revenues. The Company’s other product candidates are in clinical stage development. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained, that any products developed will obtain necessary government regulatory approval and adequate reimbursement or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapidly changing technology and substantial competition from pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees and consultants. The Company may not be able to generate significant revenue from sales of any product for several years, if at all. Accordingly, the Company will need to obtain additional capital to finance its operations. ​ The Company has a history of losses and negative cash flows from operations, and the Company expects to continue to generate operating losses and negative cash flows from operations in the foreseeable future. As of June 30, 2021, the Company had an accumulated deficit of $544,611. The Company believes that its existing cash and cash equivalents of $191,860, as of June 30, 2021, along with its current operating plan, which includes revenues from the sale of DEXTENZA, will enable it to fund its planned operating expenses, debt service obligations and capital expenditure requirements through at least the next 12 months. The future viability of the Company beyond that point is dependent on its ability to generate cash flows from the sale of DEXTENZA and raise additional capital to finance its operations. The Company will need to finance its operations through public or private securities offerings, debt financings or other sources, which may include licensing, collaborations or other strategic transactions or arrangements. Although the Company has been successful in raising capital in the past, there is no assurance that it will be successful in obtaining such additional financing on terms acceptable to the Company, if at all. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate some or all of its research and development programs for product candidates, product portfolio expansion or commercialization efforts, which could adversely affect its business prospects, or the Company may be unable to continue operations. ​ The accompanying financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). ​ Unaudited Interim Financial Information ​ The balance sheet at December 31, 2020 was derived from audited financial statements but does not include all disclosures required by GAAP. The accompanying unaudited financial statements as of June 30, 2021 and for the three and six months ended June 30, 2021 and 2020 have been prepared by the Company, pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. These financial statements should be read in conjunction with the Company’s audited financial statements and the notes thereto for the year ended December 31, 2020 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 11, 2021. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s financial position as of June 30, 2021 and results of operations and cash flows for the three and six months ended June 30, 2021 and 2020 have been made. The results of operations for the three and six months ended June 30, 2021 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2021. ​ Risks and Uncertainties ​ The Company is monitoring the potential impact of the COVID-19 pandemic, if any, on the carrying value of certain assets. To date, the Company has not experienced material business disruption, nor has it incurred impairment of any assets as a result of the COVID-19 pandemic. The extent to which these events may impact the Company’s business will depend on future developments, which are highly uncertain and cannot be predicted at this time. The duration and intensity of the COVID-19 pandemic and any resulting disruption to the Company’s operations is uncertain, and the Company will continue to assess the impact of the COVID-19 pandemic on its financial position.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies ​ Use of Estimates ​ The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting periods. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, revenue recognition, clinical trial accruals and the fair value of derivatives. Actual results may differ from these estimates. The full extent to which the COVID-19 pandemic will directly or indirectly impact the Company’s business, results of operations and financial condition, and those of its customers, vendors, suppliers, and collaboration partners, will depend on future developments that are highly uncertain, subject to change and difficult to predict, including new information that may emerge concerning COVID-19, the actions taken to contain it or treat its impact and the economic impact on local, regional, national and international customers and markets. ​ Concentration of Credit Risk and of Significant Suppliers and Customers ​ ​ The Company is dependent on a small number of third-party manufacturers to supply products for research and development activities in its preclinical and clinical programs and for sales of its products. The Company’s development programs as well as revenue from future sales of its product sales could be adversely affected by a significant interruption in the supply of any of the components of these products. ​ For the three and six months ended June 30, 2021, three specialty distributor customers accounted for 45%, 28%, and 15%, and 45%, 25% and 14% , respectively, of the Company’s total revenue, and no other customer accounted for more than 10% of the Company’s total revenue. At June 30, 2021, ​ For the three and six months ended June 30, 2020, three specialty distributor customers accounted for 48%, 16% and 14% and 41%, 19% and 14% , respectively, of the Company’s total revenue and no other customer accounted for more than 10% of total revenue. At December 31, 2020, ​ Recently Issued Accounting Pronouncements 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) (“ASU 2020-06”). This standard amends the guidance on convertible instruments and the derivatives scope exception for contracts in an entity’s own equity and improves and amends the related earnings per share guidance for both Subtopics. The amendments in the ASU are effective for public business entities that meet the definition of an SEC filer, excluding entities eligible to be smaller reporting companies as defined by the SEC, for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. The FASB also specified that an entity should adopt the guidance as of the beginning of its fiscal year and is not permitted to adopt the guidance in an interim period. The Company is assessing the potential impact of ASU 2020-06 on its condensed consolidated financial statements. ​

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities	6 Months Ended
	Jun. 30, 2021
Fair Value of Financial Assets and Liabilities
Fair Value of Financial Assets and Liabilities	3. Fair Value of Financial Assets and Liabilities ​ The following tables present information about the Company’s financial assets and liabilities that are measured at fair value on a recurring basis as of June 30, 2021 and December 31, 2020 and indicate the level of the fair value hierarchy utilized to determine such fair value: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements as of ​ ​ June 30, 2021 Using: ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ Cash equivalents: ​ ​ ​ ​ Money market funds ​ $ 187,384 ​ $ — ​ $ — ​ $ 187,384 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liability: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative liability (Note 7) ​ $ — ​ $ — ​ $ 59,901 ​ $ 59,901 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements as of ​ ​ December 31, 2020 Using: ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ Cash equivalents: ​ ​ ​ ​ Money market funds ​ $ 213,372 ​ $ — ​ $ — ​ $ 213,372 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liability: ​ ​ ​ ​ Derivative liability (Note 7) ​ $ — ​ $ — ​ $ 98,313 ​ $ 98,313 ​

Restricted Cash

Restricted Cash	6 Months Ended
	Jun. 30, 2021
Restricted Cash
Restricted Cash	4. Restricted Cash ​ The Company held restricted cash of $1,764 at June 30, 2021 and December 31, 2020, on its condensed consolidated balance sheet. The Company held restricted cash as security deposits for the lease of its manufacturing space and corporate headquarters. ​ The Company’s condensed consolidated statements of cash flows include restricted cash with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on such statements. A reconciliation of the cash, cash equivalents, and restricted cash reported within the balance sheet that sum to the total of the same amounts shown in the condensed consolidated statement of cash flows is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ June 30, ​ ​ ​ 2021 2020 Cash and cash equivalents ​ $ 191,860 ​ $ 84,294 ​ ​ Restricted cash ​ ​ 1,764 ​ ​ 1,764 ​ ​ Total cash, cash equivalents and restricted cash ​ $ 193,624 ​ $ 86,058 ​ ​ ​

Inventory

Inventory	6 Months Ended
	Jun. 30, 2021
Inventory
Inventory	5. Inventory ​ The Company values its inventories at the lower of cost or estimated net realizable value. ​ Inventory consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ ​ 2021 2020 Raw materials ​ $ 347 ​ $ 384 ​ Work-in-process ​ ​ 437 ​ ​ 232 ​ Finished goods ​ 328 ​ 585 ​ ​ ​ $ 1,112 ​ $ 1,201 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	6 Months Ended
	Jun. 30, 2021
Accrued Expenses and Other Current Liabilities
Accrued Expenses and Other Current Liabilities	6. Accrued Expenses and Other Current Liabilities ​ Accrued expenses and other current liabilities as of June 30, 2021 and December 31, 2020 consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2021 2020 Accrued payroll and related expenses ​ $ 4,873 ​ $ 5,853 Accrued rebates and programs ​ ​ 2,736 ​ ​ 1,438 Accrued professional fees ​ 1,077 ​ 868 Accrued research and development expenses ​ 1,258 ​ 1,013 Accrued interest payable on 2026 convertible notes ​ 5,325 ​ 4,194 Accrued other ​ 913 ​ 941 ​ ​ $ 16,182 ​ $ 14,307 ​

Derivative Liability

Derivative Liability	6 Months Ended
	Jun. 30, 2021
Derivative Liability
Derivative Liability	7. Derivative Liability ​ The unsecured senior subordinated convertible notes (the “2026 Convertible Notes”) (Note 8) contained an embedded conversion option that met the criteria to be bifurcated and accounted for separately (the “Derivative Liability”) from the 2026 Convertible Notes. The Derivative Liability was recorded at fair value upon the issuance of the 2026 Convertible Notes and is subsequently remeasured to fair value at each reporting period. The Derivative Liability was initially valued and remeasured using a “with-and-without” method. The “with-and-without” methodology involves valuing the whole instrument on an as-is basis and then valuing the instrument without the embedded conversion option. The difference between the entire instrument with the embedded conversion option compared to the instrument without the embedded conversion option is the fair value of the derivative, recorded as the Derivative Liability in the Company’s condensed consolidated balance sheet. ​ The estimated fair value of the 2026 Convertible Notes was $92,181 at June 30, 2021. The fair value of the 2026 Convertible Notes was estimated utilizing a binomial lattice model which requires the use of Level 3 unobservable inputs. The main input when determining the fair value for disclosure purposes is the bond yield which is updated each period to reflect the yield of a comparable instrument issued as of the valuation date. The estimated fair value presented is not necessarily indicative of an amount that could be realized in a current market exchange. The use of alternative inputs and estimation methodologies could have a material effect on these estimates of fair value. The main inputs to valuing the 2026 Convertible Notes with the conversion option are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ ​ June 30, ​ December 31, ​ ​ ​ 2021 ​ 2020 ​ Company's stock price ​ $ 14.18 ​ $ 20.70 ​ Expected annual volatility ​ ​ 97.7 % ​ 105.5 % Bond yield ​ ​ 11.9 % ​ 12.0 % ​ A roll-forward of the derivative liability is as follows: ​ ​ ​ ​ ​ ​ ​ As of Balance at December 31, 2020 ​ $ 98,313 Change in fair value ​ ​ (38,412) Balance at June 30, 2021 ​ $ 59,901 ​

Convertible Notes

Convertible Notes	6 Months Ended
	Jun. 30, 2021
Convertible Notes
Convertible Notes	8. Convertible Notes ​ On March 1, 2019, the Company issued $37,500 of 2026 Convertible Notes. Each 2026 Convertible Note accrues interest at an annual rate of 6% of its outstanding principal amount, which is payable, along with the principal amount at maturity, on March 1, 2026, unless earlier converted, repurchased or redeemed. The Company presents deferred interest in accrued current liabilities because the 2026 Convertible Notes are currently convertible and the interest is payable in cash. The effective annual interest rate for the 2026 Convertible Notes was ​ The holders of the 2026 Convertible Notes may convert all or part of the outstanding principal amount of their 2026 Convertible Notes into shares of the Company’s common stock, par value $0.0001 per share, prior to maturity and provided that no conversion results in a holder beneficially owning more than 19.99% of the issued and outstanding common stock of the Company. The conversion rate is initially 153.8462 shares of the Company’s common stock per $1,000 principal amount of the 2026 Convertible Notes, which is equivalent to an initial conversion price of $6.50 per share. The conversion rate is subject to adjustment in customary circumstances such as stock splits or similar changes to the Company’s capitalization. ​ At its election, the Company may choose to make such conversion payment in cash, in shares of common stock, or a combination thereof. Upon any conversion of any 2026 Convertible Note, the Company is obligated to make a cash payment to the holder of such 2026 Convertible Note for any interest accrued but unpaid on the principal amount converted. Upon the occurrence of a Corporate Transaction (as defined below), each holder has the option to require the Company to repurchase all or part of the outstanding principal amount of such note at a repurchase price equal to 100% of the outstanding principal amount of the 2026 Convertible Note to be repurchased, plus accrued and unpaid interest to, but excluding the repurchase date. In addition, each holder is entitled to receive an additional make-whole cash payment in accordance with a table set forth in each 2026 Convertible Note. ​ Upon conversion by the holder, the Company has the right to select the settlement of the conversion in shares of common stock, cash, or in a combination thereof. In addition, the Company is obligated to make a cash payment to the holder of such 2026 Convertible Note for any interest accrued but unpaid on the principal amount converted. ​ ● If the Company elects to satisfy such conversion by shares of common stock, the Company shall deliver to the converting holder in respect of each $1,000 principal amount of 2026 Convertible Notes being converted a number of common shares equal to the conversion rate in effect on the conversion date; ● If the Company elects to satisfy such conversion by cash settlement, the Company shall pay to the converting holder in respect of each $1,000 principal amount of 2026 Convertible Notes being converted cash in an amount equal to the sum of the Daily Conversion Values (as defined below) for each of the twenty ( 20 ) consecutive trading days during a specified period. The “Daily Conversion Values” is defined as each of the 20 consecutive trading days during the specified period, 5.0% of the product of (a) the conversion rate on such trading day and (b) the Daily VWAP on such trading day. The Daily VWAP is defined as each of the 20 consecutive trading days during the applicable observation period, the per share volume-weighted average price as displayed under the heading “Bloomberg VWAP” on the Bloomberg page for the Company. ● If the Company elects to satisfy such conversion by combination, the Company shall pay or deliver, as the case may be, in respect of each $1,000 principal amount of 2026 Convertible Notes being converted, a settlement amount equal to the sum of the Daily Settlement Amounts (as defined below) for each of the twenty ( 20 ) consecutive trading days during the specified period. The “Daily Settlement Amount” is defined as, for each of the 20 consecutive trading days during the specified period: (a) cash in an amount equal to the lesser of (i) the Daily Measurement Value (as defined below) and (ii) the Daily Conversion Value on such Trading Day; and (b) if the Daily Conversion Value on such trading day exceeds the Daily Measurement Value, a number of shares equal to (i) the difference between the Daily Conversion Value and the Daily Measurement Value, divided by (ii) the Daily VWAP for such Trading Day. The “Daily Measurement Value” is defined as the Specified Dollar Amount (as defined below) , if any, divided by 20. The “Specified Dollar Amount” is defined as the maximum cash amount per $1,000 principal amount of Notes to be received upon conversion as specified in the notice specifying the Company’s chosen settlement method. In the event of a Corporate Transaction, the noteholder shall have the right to either (a) convert all of the unpaid principal at the conversion rate and receive a cash payment equal to (i) the outstanding accrued but unpaid interest under the 2026 Convertible Note to, but excluding, the corporate transaction conversion date (to the extent such date occurs prior to March 1, 2026, the maturity date of the 2026 Convertible Notes) plus (ii) an additional amount of consideration based on a sliding scale depending on the date of such as Corporate transaction or (b) require the Company to repurchase all or part of the outstanding principal amount of such 2026 Convertible Note at a repurchase price equal to 100% of the outstanding principal amount of the 2026 Convertible Note to be repurchased, plus accrued and unpaid interest to, but excluding, the repurchase date. ​ A corporate transaction includes (i) a merger or consolidation executed through a tender offer or change of control (other than one in which stockholders of the Company own a majority by voting power of the outstanding shares of the surviving or acquiring corporation); (ii) a sale, lease, transfer, of all or substantially all of the assets of the Company; or (iii) if the Company’s common stock ceases to be listed or quoted on any of the New York Stock Exchange, the Nasdaq Global Select Market, the Nasdaq Global Market or the Nasdaq Capital Market (the “Corporate Transaction”). ​ On or after March 1, 2022, if the last reported sale price of the common stock has been at least 130% of the conversion rate then in effect for 20 of the preceding 30 trading days (including the last trading day of such period), the Company is entitled, at its option, to redeem all or part of the outstanding principal amount of the 2026 Convertible Notes, on a pro rata basis, at an optional redemption price equal to 100% of the outstanding principal amount of the 2026 Convertible Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the optional redemption date. ​ The 2026 Convertible Notes are subject to acceleration upon the occurrence of specified events of default, including a default or breach of certain contracts material to the Company and the delisting and deregistration of the Company’s common stock. ​ As discussed in Note 7, the Company determined that the embedded conversion option is required to be separated from the 2026 Convertible Notes and accounted for as a freestanding derivative instrument subject to derivative accounting. The allocation of proceeds to the conversion option results in a discount on the 2026 Convertible Notes. The Company is amortizing the discount to interest expense over the term of the 2026 Convertible Notes using the effective interest method. ​ A summary of the 2026 Convertible Notes at June 30, 2021 and December 31, 2020 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2021 2020 2026 Convertible Notes ​ $ 37,500 ​ $ 37,500 Less: unamortized discount ​ ​ (12,152) ​ ​ (13,193) Total ​ $ 25,348 ​ $ 24,307 ​ Accrued interest related to the 2026 Convertible Notes amounted to $5,325 and $4,194 at June 30, 2021 and December 31, 2020, respectively. ​

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2021
Income Taxes
Income Taxes	9. Income Taxes ​ The Company did not provide for any income taxes in its condensed consolidated statement of operations and comprehensive loss for the three and six month periods ended June 30, 2021 or 2020. The Company has provided a valuation allowance for the full amount of its net deferred tax assets because, at June 30, 2021 and December 31, 2020, it was more likely than not that any future benefit from deductible temporary differences and net operating loss and tax credit carryforwards would not be realized. ​ The Company has not recorded any amounts for unrecognized tax benefits as of June 30, 2021 or December 31, 2020. As of June 30, 2021 and December 31, 2020, the Company had accrued interest or tax penalties recorded related to income taxes. The Company’s income tax return reporting periods since December 31, 2017 are open to income tax audit examination by the federal and state tax authorities. In addition, because the Company has net operating loss carryforwards, the Internal Revenue Service is permitted to audit earlier years and propose adjustments up to the amount of net operating losses generated in those years. ​

Collaboration Agreements

Collaboration Agreements	6 Months Ended
	Jun. 30, 2021
Collaboration Agreements
Collaboration Agreements	10. Collaboration Agreements ​ AffaMed License Agreement ​ On October 29, 2020, the Company entered into license agreement (“License Agreement”) with AffaMed Therapeutic Limited (“AffaMed”) for the development and commercialization of the Company’s DEXTENZA product regarding ocular inflammation and pain following cataract surgery and allergic conjunctivitis (collectively, the “DEXTENZA Field”) and for the Company’s OTX-TIC product candidate (collectively with DEXTENZA, the “AffaMed Licensed Products”) regarding open-angle glaucoma and ocular hypertension (collectively, the “TIC Field” and, with the DEXTENZA Field, each a “Field”), in each case in mainland China, Taiwan, Hong Kong, Macau, South Korea, and the countries of the Association of Southeast Asian Nations (collectively, the “Territories”). The Company retains development and commercialization rights for the AffaMed Licensed Products in the rest of the world. ​ Under the License Agreement, the Company received a non-refundable upfront payment of $12,000 in December 2020. The Company is also eligible to receive up to an additional $91,000 in aggregate, inclusive of a low-seven-figure clinical support payment, upon the achievement of certain regulatory, development and commercial milestones. The Company is also entitled to receive tiered, escalating royalties on the net sales of the AffaMed Licensed Products ranging from a low-teen to low-twenties percentage. Royalties under the License Agreement are payable on an AffaMed Licensed Product-by-AffaMed Licensed Product and jurisdiction-by-jurisdiction basis and are subject to potential reductions in specified circumstances, subject to a specified floor. ​ The License Agreement expires upon the expiration of the last royalty term for the last AffaMed Licensed Product in any applicable Field in the Territories. Either party may, subject to specified cure periods, terminate the License Agreement in the event of the other party’s uncured breach. Either party may also terminate the License Agreement under specified circumstances relating to the other party’s insolvency. AffaMed has the right to terminate the License Agreement at any time after completion of a Phase 3 clinical trial for OTX-TIC for any or no reason upon providing the Company three months’ notice. During an established period following its change of control or its entry into a global licensing agreement that includes the Territories with a third party, the Company has the option to terminate the License Agreement, subject to a specified notice period and the repayment of any costs and expenses incurred by AffaMed in connection with the License Agreement, including upfront and milestone payments AffaMed has previously paid to the Company, at a prespecified premium. ​ At the inception of the License Agreement, the Company identified the following performance obligations in the agreement: ​ ● the license, regulatory filings and manufacturing of DEXTENZA; ​ ● the license, regulatory filings and manufacturing for the Company’s OTX-TIC product candidate regarding open-angle glaucoma and ocular hypertension in the Territories; ​ ● obligations to participate on various joint research, development and project committees; and ​ ● the conduct of a Phase 2 clinical trial of OTX-TIC ​ The Company has concluded there is a combined performance obligation for a development and commercialization license and manufacturing obligations for DEXTENZA Field and the Company’s OTX-TIC product candidate regarding open-angle glaucoma and ocular hypertension in the Territories. ​ We recognize revenue related to the amounts allocated to the combined performance obligations for DEXTENZA Field and the Company’s OTX-TIC product candidate based on the point in time upon which control of supply is transferred to AffaMed for each delivery of the associated supply. ​ The Company has not recognized any revenue under the License Agreement as of June 30, 2021 as there has not been any delivery of product under the License Agreement. The entire transaction price is recorded as deferred revenue as of June 30, 2021 and December 31, 2020. ​ Regeneron Collaboration Agreement ​ In October 2016, the Company entered into a Collaboration, Option and License Agreement (the “Collaboration Agreement”) with Regeneron Pharmaceuticals, Inc. (“Regeneron”) for the development and potential commercialization of products containing the Company’s extended-delivery hydrogel formulation in combination with Regeneron’s large molecule vascular endothelial growth factor (“VEGF”)-targeting compounds for the treatment of retinal diseases. The Collaboration Agreement does not cover the development of any product candidates that deliver small molecule drugs, including tyrosine kinase inhibitors, or TKIs, or deliver large molecule drugs other than those that target VEGF proteins. ​ Under the terms of the Collaboration Agreement, the Company and Regeneron have agreed to conduct a joint research program with the aim of developing an extended-delivery formulation of aflibercept, currently marketed under the tradename EYLEA, that is suitable for advancement into clinical development. The Company has granted Regeneron an option (the “Option”) to enter into an exclusive, worldwide license to develop and commercialize products containing the Company’s hydrogel in combination with Regeneron’s large molecule VEGF-targeting compounds (“Regeneron Licensed Products”). Under the term of the Collaboration Agreement, Regeneron is responsible for funding an initial preclinical tolerability study. ​ If the Option is exercised, Regeneron will be obligated to conduct further preclinical development and an initial clinical trial under a collaboration plan. The Company is obligated to reimburse Regeneron for certain development costs incurred by Regeneron under the collaboration plan during the period through the completion of the initial clinical trial, subject to a cap of under certain circumstances. If Regeneron elects to proceed with further development following the completion of the collaboration plan, it will be solely responsible for conducting and funding further development and commercialization of product candidates. If the Option is exercised, Regeneron is required to use commercially reasonable efforts to research, develop and commercialize at least one Regeneron Licensed Product. Such efforts shall include initiating the dosing phase of a subsequent clinical trial within specified time periods following the completion of the first-in-human clinical trial or the initiation of preclinical toxicology studies, subject to certain extensions. ​ Under the terms of the Collaboration Agreement, Regeneron has agreed to pay the Company $10,000 upon the exercise of the Option. If Regeneron elects to exercise the Option, the Company is also eligible to receive up to $100,000 per Regeneron Licensed Product upon first commercial sale of such Regeneron Licensed Product and up to $50,000 based on the achievement of specified sales milestones for all Regeneron Licensed Products. In addition, the Company is entitled to tiered, escalating royalties, in a range from a high-single digit to a low-to-mid teen percentage of net sales of Regeneron Licensed Products. ​ In December 2017, the Company delivered to Regeneron a proposed final formulation for the initial preclinical tolerability study. Regeneron initiated the preclinical study in early 2018. The Company and Regeneron subsequently reached an understanding that the proposed formulation was not final and ceased development of it. On May 8, 2020, the Company entered into an amendment (the “Amendment”) to the Collaboration Agreement. Pursuant to the Amendment, the Company and Regeneron have adopted a new work plan to transition joint efforts under the Collaboration Agreement to the research and development of an extended-delivery formulation of aflibercept to be delivered to the suprachoroidal space. Regeneron has agreed to pay personnel and material costs of the Company for specified preclinical development activities in connection with the revised work plan, as well as certain other costs. In addition, the Amendment provides for the modification of the terms of the Option previously granted to Regeneron under the Collaboration Agreement. As amended, the Option is exclusive for twenty-four months following May 8, 2020. Through June 30, 2021, the Option has not been exercised, and no payments have been made. For the three and six months ended June 30, 2021, the Company has recorded $418 and $515, respectively, related to work performed for preclinical development activities in connection with the revised work plan which the Company has recorded as a reduction of research and development expense as this research is not an output of the Company’s ordinary business activities. As of June 30, 2021 and December 31, 2020, the Company has included the $934 and $1,256, respectively in prepaid expenses and other current assets. As further described under Note 18, on August 5, 2021, Regeneron notified the Company of its termination of the Collaboration Agreement. The termination became effective immediately.

Notes Payable

Notes Payable	6 Months Ended
	Jun. 30, 2021
Notes Payable
Notes payable	11. Notes Payable ​ The Company entered into a credit and security agreement in 2014 (as amended to date, the “Credit Agreement”) establishing the Company’s credit facility (the “Credit Facility”). The Company has a total borrowing capacity of ​ In December 2018, the Company amended the terms of the Credit Agreement to increase total indebtedness under the Credit Facility to $25,000 , which was used primarily to pay-off outstanding balances as of the closing date. The Company was required to make interest-only payments under the Credit Facility until December 2020. Commencing in January 2021, the Company was required to make . The exit fee equal to ​ In June 2021, the Company entered into a Fourth Amended and Restated Credit and Security Agreement (the “Fourth Amendment”) to amend the terms of its debt with existing lenders for total indebtedness of Amounts borrowed under the 2021 Amended Credit Facility are at LIBOR base rate, subject to 1.00% floor, plus 6.75%. The interest rate on the date of the amendment was 8.8%. In addition, a final payment (exit fee) equal to 3.5% of amounts drawn under the Amended Credit Facility, or $875 based on borrowings of $25,000, is due upon the maturity date of November 30, 2025. The Company is accruing the exit fee through November 30, 2025. ​ The Company accounted for the Fourth Amendment as a modification in accordance with the guidance in ASC 470-50, Debt. Amounts paid to the lenders were recorded as debt discount and a new effective interest rate was established. The effective annual interest rate of the outstanding debt under the Fourth Amendment is . ​ There are no financial covenants associated with the Fourth Amendment. However, the Fourth Amendment does contain negative covenants restricting the Company’s activities, including limitations on dispositions, mergers or acquisitions; encumbering its intellectual property; incurring indebtedness or liens; paying dividends; making certain investments; and engaging in certain other business transactions. As of June 30, 2021, the Company was not in violation of any of its covenants under the Fourth Amendment. The obligations under the Fourth Amendment are subject to acceleration upon the occurrence of specified events of default, including a material adverse change in the Company’s business, operations or financial or other condition. The debt is collateralized by substantially all of the Company’s assets, including its intellectual property. ​ In accordance with the 2021 Amended Credit Facility, among other provisions, a negative covenant restricting the Company from paying the holders of the 2026 Convertible Notes ahead in priority to the existing lenders, for so long as indebtedness remains outstanding under the Credit Facility, and a cross-default provision to establish that an event of default under the purchase agreement for the 2026 Convertible Notes also constitutes an event of default under the Fourth Amendment. ​ Borrowings outstanding are as follows : ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ 2021 2020 Borrowings outstanding ​ $ 25,000 ​ $ 25,000 Accrued exit fee ​ ​ 15 ​ ​ 355 Unamortized discount ​ ​ (124) ​ ​ (129) ​ ​ ​ 24,891 ​ ​ 25,226 Less: current portion ​ ​ — ​ ​ (8,290) Long-term notes payable ​ $ 24,891 ​ $ 16,936 ​ As of June 30, 2021, the annual repayment requirements for the Credit Facility, inclusive of the final payment of $875 due at expiration, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ending December 31, Principal Final Payment Total 2021 (July 1 through December 31) ​ ​ — ​ ​ — ​ ​ — 2022 ​ ​ — ​ ​ — ​ ​ — 2023 ​ ​ — ​ ​ — ​ ​ — 2024 ​ ​ 8,333 ​ ​ — ​ ​ 8,333 2025 ​ ​ 16,667 ​ ​ 875 ​ ​ 17,542 ​ ​ $ 25,000 ​ $ 875 ​ $ 25,875 ​ ​

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2021
Net Loss Per Share
Net Loss Per Share	12. Net Loss Per Share ​ Basic net loss per share was calculated as follows for the three and six months ended June 30, 2021 and 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 ​ 2020 ​ 2021 ​ 2020 Numerator: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss attributable to common stockholders ​ $ (8,481) ​ $ (36,568) ​ $ (5,360) ​ $ (58,080) Denominator: ​ ​ ​ ​ ​ ​ Weighted average common shares outstanding ​ 76,324,367 ​ 57,368,292 ​ 76,198,384 ​ 54,634,572 Net loss per share - basic ​ $ (0.11) ​ $ (0.64) ​ $ (0.07) ​ $ (1.06) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the three and six months ended June 30, 2020, there is no dilutive impact. Therefore, diluted net loss per share is the same as basic net loss per share. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ ​ Six Months Ended June 30, ​ 2021 ​ ​ 2021 ​ Net income attributable to common stockholders, basic ​ $ (8,481) ​ ​ $ (5,360) — Interest expense on 2026 Convertible Notes ​ 1,095 ​ ​ 2,173 ​ Change in fair value of derivative liability ​ ​ (13,396) ​ ​ ​ (38,412) ​ Net loss attributable to common stockholders, diluted ​ $ (20,782) ​ ​ $ (41,599) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average common shares outstanding, basic ​ ​ 76,324,367 ​ ​ ​ 76,198,384 ​ Shares issuable upon conversion of 2026 Convertible Notes, as if converted ​ ​ 5,769,232 ​ ​ ​ 5,769,232 ​ Weighted average common shares outstanding, diluted ​ 82,093,599 ​ ​ 81,967,616 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss per share attributable to common stockholders, diluted ​ $ (0.25) ​ ​ $ (0.51) ​ ​ The Company excluded the following common stock equivalents, outstanding as of June 30, 2021 and 2020, from the computation of diluted net loss per share for the three and six months ended June 30, 2021 and 2020 because they had an anti-dilutive impact. ​ ​ ​ ​ ​ ​ ​ ​ Six Months ended June 30, ​ 2021 2020 Options to purchase common stock ​ 11,049,287 ​ 9,270,173 Warrants for the purchase of common stock ​ — ​ 18,939 ​ ​ 11,049,287 ​ 9,289,112 ​ The Company also excluded the shares issuable upon conversion of the 2026 Convertible notes from the computation of diluted net loss per share for the three and six months ended June 30, 2020 because they had an anti-dilutive impact.

Stock-Based Awards

Stock-Based Awards	6 Months Ended
	Jun. 30, 2021
Stock-Based Awards
Stock-Based Awards	13. Stock-Based Awards ​ 2014 Stock Incentive Plan ​ The 2014 Stock Incentive Plan (the “2014 Plan”) provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock units, stock appreciation rights and other stock-based awards. The number of shares of common stock that may be issued under the 2014 Plan is subject to increase on the first day of each fiscal year, beginning on January 1, 2015 and ending on December 31, 2024 in an amount equal to the lesser of a pre-determined formula or an amount determined by the Company’s board of directors. On January 1, 2021, the number of shares available for issuance under the 2014 Plan was increased by . During the three and six months ended June 30, 2021, the Company granted options to purchase 229,650 and 2,709,019 shares of common stock, at a weighted exercise price of $16.54 and $18.19 per share, respectively. ​ On June 18, 2021, the Company’s stockholders approved the adoption of the 2021 Stock Incentive Plan (the “2021 Plan”) previously approved by the board of directors. Effective as of the adoption of the 2021 Plan by the Company’s stockholders, no new awards will be granted under the 2014 Plan. However, as of June 30, 2021, all then-outstanding awards under the 2014 Plan remained in effect and continued to be governed by the terms of the 2014 Plan. ​ 2021 Stock Incentive Plan ​ The 2021 Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock units, stock appreciation rights and other stock-based awards. The number of shares of common stock that may be issued under the 2021 Plan is ​ 2014 Employee Stock Purchase Plan ​ The Company has a 2014 Employee Stock Purchase Plan (the “ESPP”). The number of shares of common stock that may be issued under the ESPP will automatically increase on the first day of each fiscal year, commencing on January 1, 2015 and ending on December 31, 2024 in an amount equal to the lesser of a pre-determined formula or as determined by the Company’s board of directors. On January 1, 2021, the number of shares available for issuance under the 2014 Plan was increased by . During the three months ended June 30, 2021, shares of common stock were issued under the ESPP. As of June 30, 2021, shares remained available for issuance under the ESPP. ​ Inducement Stock Option Awards ​ On October 29, 2019, the 2019 Inducement Stock Incentive Plan (the “Inducement Plan”) was approved by the Board of Directors of the Company. Initially, the maximum number of shares of common stock issuable under the Inducement Plan was 500,000 . On December 10, 2020, the Board of Directors of the Company amended the 2019 Inducement Plan to increase the aggregate number of shares issuable from 500,000 to 1,054,000 ​ Stock-based Compensation ​ The Company recorded stock-based compensation expense related to stock options in the following expense categories of its condensed consolidated statements of operations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ June 30, ​ June 30, ​ ​ 2021 2020 2021 2020 Research and development ​ $ 1,206 ​ $ 362 ​ $ 1,883 ​ $ 737 ​ Selling and marketing ​ 1,129 ​ 433 ​ 1,883 ​ 804 ​ General and administrative ​ 1,957 ​ 1,031 ​ 3,612 ​ 1,950 ​ ​ ​ $ 4,292 ​ $ 1,826 ​ $ 7,378 ​ $ 3,491 ​ ​ ​ As of June 30, 2021, the Company had an aggregate of $26,106 of unrecognized stock-based compensation cost, which is expected to be recognized over a weighted average period of 3.2 years.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments and Contingencies.
Commitments and Contingencies	14. Commitments and Contingencies ​ Collaboration Agreement ​ On October 10, 2016, the Company entered into the Collaboration Agreement with Regeneron, which the parties amended in May 2020 (Note 10). If the Option to enter into an exclusive worldwide license is exercised, Regeneron will be obligated to conduct further preclinical development and an initial clinical trial under a collaboration plan. The Company is obligated to reimburse Regeneron for certain development costs incurred by Regeneron under the collaboration plan during the period through the completion of the initial clinical trial, subject to a cap of under certain circumstances; the timing of such payments are not known. If Regeneron elects to proceed with further development following the completion of the collaboration plan, it will be solely responsible for conducting and funding further development and commercialization of product candidates. If the Option is exercised, Regeneron is required to use commercially reasonable efforts to research, develop and commercialize at least one Regeneron Licensed Product. Such efforts shall include initiating the dosing phase of a subsequent clinical trial within specified time periods following the completion of the first-in-human clinical trial or the initiation of preclinical toxicology studies, subject to certain extensions. As further described under Note 18, on August 5, 2021, Regeneron notified the Company of its termination of the Collaboration Agreement. The termination became effective immediately. ​

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2021
Related Party Transactions
Related Party Transactions	15. Related Party Transactions ​ Since October 2017, the Company has engaged McCarter English LLP (“McCarter”) to provide legal services to the Company, including with respect to intellectual property matters. Jonathan M. Sparks, Ph.D., a partner at McCarter & English, also served as the Company’s in-house counsel from October 2017 through August 31, 2020. The Company incurred fees for legal services rendered by McCarter of $221 and $512 for the three and six months ended June 30, 2020, respectively. As of December 31, 2020, there was ​ Since November 2020, the Company has engaged Specialty Pharma Consulting, LLC (“Specialty Pharma”), an entity affiliated with Kevin Coughenour, to provide services for quality engineering and validation activities in the ordinary course of business. Mr. Coughenour is married to the Company’s former Chief Operating Officer Patricia Kitchen. The Company incurred fees for quality engineering and validation activities rendered by Specialty Pharma of $29 and $155 , for the three and six months ended June 30, 2021, respectively. As of December 31, 2020, there was recorded in accrued expenses for Specialty Pharma. On April 26, 2021, the Company and Specialty Pharma terminated their relationship. ​

Warrants

Warrants	6 Months Ended
	Jun. 30, 2021
Warrants
Warrants	16. Warrants ​ On January 29, 2021, holders of warrants to purchase 18,939 shares of common stock at an exercise price of $7.92 exercised their right to purchase their warrants. The exercise price of the warrants was paid through a net share settlement mechanism and as a result the Company issued shares of common stock to satisfy the exercise of all the warrants. There are

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2021
Common Stock
Common Stock	17. Common Stock In June 2021, the Company adopted an amended and restated certificate of incorporation increasing the number of its authorized shares of its common stock to 200,000,000 shares.

Subsequent Event

Subsequent Event	6 Months Ended
	Jun. 30, 2021
Subsequent Event
Subsequent Event	18. Subsequent Event On August 5, 2021, Regeneron notified the Company of its termination of the Collaboration Agreement for convenience, in accordance with the terms of the Collaboration Agreement. The termination became effective immediately, subject to specified surviving rights and obligations thereunder. ​ In connection with the termination of the Collaboration Agreement, all licenses, options and other rights granted to either party under the Collaboration Agreement automatically terminated, other than the surviving joint intellectual property rights described below. The Company and Regeneron also became obligated to undertake certain transition activities upon the termination, including the return of specified property of the other party. Each party retains an equal, undivided ownership interest, which may be transferred, licensed and otherwise exploited without a duty to account to the other party, in certain intellectual property rights jointly developed under the collaboration. ​ As a result of the termination, the Company is no longer eligible to receive (i) reimbursement from Regeneron for ongoing research and development activities, (ii) a fee upon exercise of the Option, (iii) payments upon the achievement of specified development and regulatory milestones of the Regeneron Licensed Products, or (iv) tiered, escalating royalties in a range from a high-single digit to a low-to-mid teen percentage of net sales of Regeneron Licensed Products, in each case pursuant to the Collaboration Agreement. The Company is also no longer obligated to reimburse Regeneron for certain development costs, up to an aggregate amount of $30,000 in certain circumstances, were Regeneron to have exercised the Option. ​

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
Summary of Significant Accounting Policies
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 reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting periods. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, revenue recognition, clinical trial accruals and the fair value of derivatives. Actual results may differ from these estimates. The full extent to which the COVID-19 pandemic will directly or indirectly impact the Company’s business, results of operations and financial condition, and those of its customers, vendors, suppliers, and collaboration partners, will depend on future developments that are highly uncertain, subject to change and difficult to predict, including new information that may emerge concerning COVID-19, the actions taken to contain it or treat its impact and the economic impact on local, regional, national and international customers and markets.
Concentration of Credit Risk and of Significant Suppliers and Customers	Concentration of Credit Risk and of Significant Suppliers and Customers ​ ​ The Company is dependent on a small number of third-party manufacturers to supply products for research and development activities in its preclinical and clinical programs and for sales of its products. The Company’s development programs as well as revenue from future sales of its product sales could be adversely affected by a significant interruption in the supply of any of the components of these products. ​ For the three and six months ended June 30, 2021, three specialty distributor customers accounted for 45%, 28%, and 15%, and 45%, 25% and 14% , respectively, of the Company’s total revenue, and no other customer accounted for more than 10% of the Company’s total revenue. At June 30, 2021, ​ For the three and six months ended June 30, 2020, three specialty distributor customers accounted for 48%, 16% and 14% and 41%, 19% and 14% , respectively, of the Company’s total revenue and no other customer accounted for more than 10% of total revenue. At December 31, 2020, ​
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements 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) (“ASU 2020-06”). This standard amends the guidance on convertible instruments and the derivatives scope exception for contracts in an entity’s own equity and improves and amends the related earnings per share guidance for both Subtopics. The amendments in the ASU are effective for public business entities that meet the definition of an SEC filer, excluding entities eligible to be smaller reporting companies as defined by the SEC, for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. The FASB also specified that an entity should adopt the guidance as of the beginning of its fiscal year and is not permitted to adopt the guidance in an interim period. The Company is assessing the potential impact of ASU 2020-06 on its condensed consolidated financial statements.

Fair Value of Financial Asset_2

Fair Value of Financial Assets and Liabilities (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value of Financial Assets and Liabilities
Schedule of assets and liabilities measured at fair Value on recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements as of ​ ​ June 30, 2021 Using: ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ Cash equivalents: ​ ​ ​ ​ Money market funds ​ $ 187,384 ​ $ — ​ $ — ​ $ 187,384 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liability: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative liability (Note 7) ​ $ — ​ $ — ​ $ 59,901 ​ $ 59,901 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements as of ​ ​ December 31, 2020 Using: ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ Cash equivalents: ​ ​ ​ ​ Money market funds ​ $ 213,372 ​ $ — ​ $ — ​ $ 213,372 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liability: ​ ​ ​ ​ Derivative liability (Note 7) ​ $ — ​ $ — ​ $ 98,313 ​ $ 98,313

Restricted Cash (Tables)

Restricted Cash (Tables)	6 Months Ended
	Jun. 30, 2021
Restricted Cash
Reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheet to the total amounts shown in the statement of cash flows	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ June 30, ​ ​ ​ 2021 2020 Cash and cash equivalents ​ $ 191,860 ​ $ 84,294 ​ ​ Restricted cash ​ ​ 1,764 ​ ​ 1,764 ​ ​ Total cash, cash equivalents and restricted cash ​ $ 193,624 ​ $ 86,058 ​ ​

Inventory (Tables)

Inventory (Tables)	6 Months Ended
	Jun. 30, 2021
Inventory
Components of inventory	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ ​ 2021 2020 Raw materials ​ $ 347 ​ $ 384 ​ Work-in-process ​ ​ 437 ​ ​ 232 ​ Finished goods ​ 328 ​ 585 ​ ​ ​ $ 1,112 ​ $ 1,201 ​ ​ ​ ​ ​ ​ ​ ​ ​

Accrued Expenses and other cu_2

Accrued Expenses and other current liabilities (Tables)	6 Months Ended
	Jun. 30, 2021
Accrued Expenses and Other Current Liabilities
Schedule of accrued expenses and other current liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2021 2020 Accrued payroll and related expenses ​ $ 4,873 ​ $ 5,853 Accrued rebates and programs ​ ​ 2,736 ​ ​ 1,438 Accrued professional fees ​ 1,077 ​ 868 Accrued research and development expenses ​ 1,258 ​ 1,013 Accrued interest payable on 2026 convertible notes ​ 5,325 ​ 4,194 Accrued other ​ 913 ​ 941 ​ ​ $ 16,182 ​ $ 14,307

Derivative Liability (Tables)

Derivative Liability (Tables)	6 Months Ended
	Jun. 30, 2021
Derivative Liability
Schedule of main inputs to valuing the 2026 Convertible Notes with the conversion option	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ ​ June 30, ​ December 31, ​ ​ ​ 2021 ​ 2020 ​ Company's stock price ​ $ 14.18 ​ $ 20.70 ​ Expected annual volatility ​ ​ 97.7 % ​ 105.5 % Bond yield ​ ​ 11.9 % ​ 12.0 %
Summary of roll-forward of the derivative liability	​ ​ ​ ​ ​ ​ ​ As of Balance at December 31, 2020 ​ $ 98,313 Change in fair value ​ ​ (38,412) Balance at June 30, 2021 ​ $ 59,901

Convertible Notes (Tables)

Convertible Notes (Tables)	6 Months Ended
	Jun. 30, 2021
Convertible Notes
Summary of the 2026 Convertible Notes	A summary of the 2026 Convertible Notes at June 30, 2021 and December 31, 2020 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2021 2020 2026 Convertible Notes ​ $ 37,500 ​ $ 37,500 Less: unamortized discount ​ ​ (12,152) ​ ​ (13,193) Total ​ $ 25,348 ​ $ 24,307

Notes Payable (Tables)

Notes Payable (Tables)	6 Months Ended
	Jun. 30, 2021
Notes Payable
Schedule of borrowings outstanding	​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ 2021 2020 Borrowings outstanding ​ $ 25,000 ​ $ 25,000 Accrued exit fee ​ ​ 15 ​ ​ 355 Unamortized discount ​ ​ (124) ​ ​ (129) ​ ​ ​ 24,891 ​ ​ 25,226 Less: current portion ​ ​ — ​ ​ (8,290) Long-term notes payable ​ $ 24,891 ​ $ 16,936
Schedule of Annual Repayment Requirements for Credit Facility	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ending December 31, Principal Final Payment Total 2021 (July 1 through December 31) ​ ​ — ​ ​ — ​ ​ — 2022 ​ ​ — ​ ​ — ​ ​ — 2023 ​ ​ — ​ ​ — ​ ​ — 2024 ​ ​ 8,333 ​ ​ — ​ ​ 8,333 2025 ​ ​ 16,667 ​ ​ 875 ​ ​ 17,542 ​ ​ $ 25,000 ​ $ 875 ​ $ 25,875

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2021
Net Loss Per Share
Schedule of basic and diluted net loss per share attributable to common stockholders	Basic net loss per share was calculated as follows for the three and six months ended June 30, 2021 and 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 ​ 2020 ​ 2021 ​ 2020 Numerator: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss attributable to common stockholders ​ $ (8,481) ​ $ (36,568) ​ $ (5,360) ​ $ (58,080) Denominator: ​ ​ ​ ​ ​ ​ Weighted average common shares outstanding ​ 76,324,367 ​ 57,368,292 ​ 76,198,384 ​ 54,634,572 Net loss per share - basic ​ $ (0.11) ​ $ (0.64) ​ $ (0.07) ​ $ (1.06) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the three and six months ended June 30, 2020, there is no dilutive impact. Therefore, diluted net loss per share is the same as basic net loss per share. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ ​ Six Months Ended June 30, ​ 2021 ​ ​ 2021 ​ Net income attributable to common stockholders, basic ​ $ (8,481) ​ ​ $ (5,360) — Interest expense on 2026 Convertible Notes ​ 1,095 ​ ​ 2,173 ​ Change in fair value of derivative liability ​ ​ (13,396) ​ ​ ​ (38,412) ​ Net loss attributable to common stockholders, diluted ​ $ (20,782) ​ ​ $ (41,599) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average common shares outstanding, basic ​ ​ 76,324,367 ​ ​ ​ 76,198,384 ​ Shares issuable upon conversion of 2026 Convertible Notes, as if converted ​ ​ 5,769,232 ​ ​ ​ 5,769,232 ​ Weighted average common shares outstanding, diluted ​ 82,093,599 ​ ​ 81,967,616 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss per share attributable to common stockholders, diluted ​ $ (0.25) ​ ​ $ (0.51) ​
Schedule of antidilutive securities, excluded from computation of diluted net loss per share	​ ​ ​ ​ ​ ​ ​ Six Months ended June 30, ​ 2021 2020 Options to purchase common stock ​ 11,049,287 ​ 9,270,173 Warrants for the purchase of common stock ​ — ​ 18,939 ​ ​ 11,049,287 ​ 9,289,112

Stock-Based Awards (Tables)

Stock-Based Awards (Tables)	6 Months Ended
	Jun. 30, 2021
Stock-Based Awards
Schedule of stock-based compensation expense related to stock options	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ June 30, ​ June 30, ​ ​ 2021 2020 2021 2020 Research and development ​ $ 1,206 ​ $ 362 ​ $ 1,883 ​ $ 737 ​ Selling and marketing ​ 1,129 ​ 433 ​ 1,883 ​ 804 ​ General and administrative ​ 1,957 ​ 1,031 ​ 3,612 ​ 1,950 ​ ​ ​ $ 4,292 ​ $ 1,826 ​ $ 7,378 ​ $ 3,491 ​

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation - Nature of Business (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Nature of the Business and Basis of Presentation
Accumulated deficit	$ 544,611	$ 539,251
Cash and cash equivalents	$ 191,860	$ 228,057	$ 84,294

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Concentration of Credit Risk (Details) - Customer - customer	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Total revenue
Concentration risk
Number of major customers	3	3	3	3
Total revenue | Customer one
Concentration risk
Concentration risk	45.00%	48.00%	45.00%	41.00%
Total revenue | Customer two
Concentration risk
Concentration risk	28.00%	16.00%	25.00%	19.00%
Total revenue | Customer three
Concentration risk
Concentration risk	15.00%	14.00%	14.00%	14.00%
Accounts receivable
Concentration risk
Number of major customers			3		3
Accounts receivable | Customer one
Concentration risk
Concentration risk			51.00%		45.00%
Accounts receivable | Customer two
Concentration risk
Concentration risk			27.00%		33.00%
Accounts receivable | Customer three
Concentration risk
Concentration risk			14.00%		15.00%

Fair Value of Financial Asset_3

Fair Value of Financial Assets and Liabilities - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Liability:
Derivative liability	$ 59,901	$ 98,313
Recurring Basis
Liability:
Derivative liability	59,901	98,313
Money Market Funds | Recurring Basis
Assets:
Cash equivalents	187,384	213,372
Level 1 | Money Market Funds | Recurring Basis
Assets:
Cash equivalents	187,384	213,372
Level 3 | Recurring Basis
Liability:
Derivative liability	$ 59,901	$ 98,313

Restricted Cash (Details)

Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Restricted Cash
Cash and cash equivalents	$ 191,860	$ 228,057	$ 84,294
Restricted cash	1,764	1,764	1,764
Total cash, cash equivalents and restricted cash as shown on the statements of cash flows	$ 193,624	$ 229,821	$ 86,058	$ 56,201

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Inventory
Raw materials	$ 347	$ 384
Work-in-process	437	232
Finished goods	328	585
Total inventory	$ 1,112	$ 1,201

Accrued Expenses and other cu_3

Accrued Expenses and other current liabilities - Summary (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accrued Expenses and Other Current Liabilities
Accrued payroll and related expenses	$ 4,873	$ 5,853
Accrued rebates and programs	2,736	1,438
Accrued professional fees	1,077	868
Accrued research and development expenses	1,258	1,013
Accrued interest payable on 2026 convertible notes	5,325	4,194
Accrued other	913	941
Total	$ 16,182	$ 14,307

Derivative Liability - Main Inp

Derivative Liability - Main Inputs to Valuing Convertible Notes with Conversion Option (Details) - 2026 Convertible Notes $ in Thousands	Jun. 30, 2021USD ($)	Dec. 31, 2020
Derivative Liability
Estimated fair value	$ 92,181
Conversion price
Derivative Liability
Debt instrument, measurement input	14.18	20.70
Expected annual volatility
Derivative Liability
Debt instrument, measurement input	97.7	105.5
Discount yield
Derivative Liability
Debt instrument, measurement input	11.9	12

Derivative Liability - Roll for

Derivative Liability - Roll forward (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)
Roll forward of the derivative liability
Balance at beginning of period	$ 98,313
Change in fair value	(38,412)
Balance at end of period	$ 59,901

Convertible Notes - Other (Deta

Convertible Notes - Other (Details)	Mar. 01, 2019USD ($)D$ / shares	Jun. 30, 2021USD ($)$ / shares	Dec. 31, 2020USD ($)$ / shares
Senior Convertible Notes
Common stock, par value | $ / shares		$ 0.0001	$ 0.0001
2026 Convertible Notes
Senior Convertible Notes
Convertible notes issued | $	$ 37,500,000	$ 37,500,000	$ 37,500,000
Interest rate (as a percent)	6.00%
Effective annual interest rate (as a percent)		14.80%
Common stock, par value | $ / shares	$ 0.0001
Maximum beneficial ownership percent	19.99%
Conversion rate	153.8462
Principal amount of debt that is used in conversion calculations | $	$ 1,000
Initial conversion price | $ / shares	$ 6.50
Debt repurchase price percent	100.00%
Consecutive trading days | D	20
Percentage of product of conversion rate and daily VWAP	5.00%
Percentage of outstanding principal amount	100.00%
2026 Convertible Notes | On or after March 1, 2022
Senior Convertible Notes
Debt repurchase price percent	100.00%
Consecutive trading days | D	30
Minimum percentage of common stock for conversion of debt	130.00%
Consecutive proceeding trading days for conversion of purchase price | $	20

Convertible Notes - Summary (De

Convertible Notes - Summary (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Mar. 01, 2019
Senior Convertible Notes
Less: unamortized discount	$ (124)	$ (129)
2026 Convertible Notes
Senior Convertible Notes
Convertible notes	37,500	37,500	$ 37,500
Less: unamortized discount	(12,152)	(13,193)
Total	25,348	24,307
Accrued interest	$ 5,325	$ 4,194

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Income Taxes
Unrecognized tax benefits	$ 0	$ 0
Accrued interest or tax penalties related to income taxes	$ 0	$ 0

Collaboration Agreements - Addi

Collaboration Agreements - Additional Information (Details) - USD ($) $ in Thousands	Oct. 28, 2020	Oct. 10, 2016	Jun. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
License Agreement | AffaMed
Collaboration Agreement
Amount of non-refundable upfront payments received					$ 12,000
Additional payments to be received upon the achievement of certain development and commercial milestones	$ 91,000
Collaboration Agreement | Regeneron
Collaboration Agreement
Payment receivable upon exercise of option		$ 10,000
Amount of cost recorded, to date, for work performed for preclinical development activities in connection with the revised work plan			$ 418	$ 515
Costs associated with preclinical development activities included in prepaid expenses and other current assets			$ 934	$ 934	$ 1,256
Collaboration Agreement | Regeneron | Maximum
Collaboration Agreement
Reimbursable clinical development costs		25,000
Potential increase in reimbursable clinical development costs		5,000
Potential payment receivable per Licensed Product upon the achievement of specified development and regulatory milestones		145,000
Potential payment receivable per Licensed Product upon first commercial sale of such Licensed Product		100,000
Potential payment receivable due for achievement of specified sales milestones for all Licensed Products		$ 50,000

Notes Payable - Additional Info

Notes Payable - Additional Information (Details)	1 Months Ended
	Jun. 30, 2021USD ($)	Jan. 31, 2021USD ($)installment	Dec. 31, 2018USD ($)	May 31, 2021	Dec. 31, 2020USD ($)
Notes Payable
Borrowing capacity under the agreement	$ 25,000,000
Borrowings outstanding	25,000,000				$ 25,000,000
Credit Agreement, 2018
Notes Payable
Outstanding borrowings under credit facility, net of unamortized discount			$ 25,000,000
Debt Instrument, Percentage of Exit Fee			3.50%
Accrued amount paid			$ 429,000
Credit Agreement, 2018 | Period commencing January 2021
Notes Payable
Number of equal monthly installments | installment		36
Required monthly principal payment		$ 694,000
Credit Agreement, 2018 | LIBOR
Notes Payable
Interest rate (as a percent)				9.25%
Interest rate floor (as a percent)			2.00%
Basis spread (as a percent)			7.25%
2021 Amended Credit Facility
Notes Payable
Borrowings outstanding	25,000,000
Indebtedness with existing lenders in which terms of credit facility were amended, amount	20,833,000
Incremental borrowing, amount	4,167,000
Final payment due at maturity	$ 5,208,000
Effective annual interest rate (as a percent)	8.80%
Exit fee (as a percent)	3.50%
Exit fee, amount	$ 875,000
Additional final payment	$ 875,000
2021 Amended Credit Facility | Period commencing May 2024
Notes Payable
Number of equal monthly installments	19
Required monthly principal payment	$ 1,042,000
2021 Amended Credit Facility | Achievement of certain milestones
Notes Payable
Number of equal monthly installments	5
Required monthly principal payment	$ 1,042,000
2021 Amended Credit Facility | LIBOR
Notes Payable
Interest rate floor (as a percent)	1.00%
Basis spread (as a percent)	6.75%

Notes Payable - Borrowings Outs

Notes Payable - Borrowings Outstanding (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Notes Payable
Borrowings outstanding	$ 25,000	$ 25,000
Accrued exit fee	15	355
Less: unamortized discount	124	129
Borrowings	24,891	25,226
Less: current portion		(8,290)
Long-term notes payable	$ 24,891	$ 16,936

Notes Payable - Schedule of Ann

Notes Payable - Schedule of Annual Repayment Requirements for Credit Facility (Details) - 2021 Amended Credit Facility $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)
Annual repayment requirements
Credit Facility, Principal	$ 25,000
Credit Facility, Final Payment	875
Credit Facility, Total	25,875
2024
Annual repayment requirements
Credit Facility, Principal	8,333
Credit Facility, Total	8,333
2025
Annual repayment requirements
Credit Facility, Principal	16,667
Credit Facility, Final Payment	875
Credit Facility, Total	$ 17,542

Net Loss Per Share - Basic Net

Net Loss Per Share - Basic Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Basic net loss per share attributable to common stockholders:
Net loss attributable to common stockholders	$ (8,481)	$ 3,121	$ (36,568)	$ (21,512)	$ (5,360)	$ (58,080)
Weighted average common shares outstanding, basic	76,324,367		57,368,292		76,198,384	54,634,572
Net loss per share - basic	$ (0.11)		$ (0.64)		$ (0.07)	$ (1.06)

Net Loss Per Share - Diluted Ne

Net Loss Per Share - Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Reconciliation of net loss attributable to common stockholders for basic and diluted net loss per share
Net loss attributable to common stockholders, basic	$ (8,481)		$ (5,360)
Interest expense on 2026 Convertible Note	1,095		2,173
Change in fair value of derivative liability	(13,396)		(38,412)
Net loss attributable to common stockholders, diluted	$ (20,782)		$ (41,599)
Weighted average common shares outstanding, basic	76,324,367	57,368,292	76,198,384	54,634,572
Shares issuable upon conversion of 2026 Convertible Note, as if converted	5,769,232		5,769,232
Weighted average common shares outstanding, diluted	82,093,599	57,368,292	81,967,616	54,634,572
Net loss per share attributable to common stockholders diluted	$ (0.25)	$ (0.64)	$ (0.51)	$ (1.06)

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Antidilutive Securities, Excluded from Computation of Diluted Net Loss per Share (Details) - shares	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total common stock equivalents	11,049,287	9,289,112
Options to Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total common stock equivalents	11,049,287	9,270,173
Warrant | Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total common stock equivalents		18,939

Stock-Based Awards - Additional

Stock-Based Awards - Additional Information (Details) - $ / shares	3 Months Ended			6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jan. 01, 2021
Common Stock
Stock-Based Awards
Issuance of common stock in connection with employee stock purchase plan	40,631	104,579
Issuance of common stock upon public offering, net of issuance costs, shares		9,735,649	2,657,823
2014 Stock Incentive Plan | Common Stock
Stock-Based Awards
Increased number of shares of common stock reserved for issuance					1,659,218
Shares Issuable Under Options, Granted	229,650			2,709,019
Exercise price (in dollars per share)	$ 16.54			$ 18.19
2014 Employee Stock Purchase Plan | Common Stock
Stock-Based Awards
Increased number of shares of common stock reserved for issuance					207,402
Issuance of common stock in connection with employee stock purchase plan	40,631
Number of shares of common stock available for issuance	690,965			690,965
2021 Incentive Plan
Stock-Based Awards
Number of shares of common stock authorized for issuance	6,000,000			6,000,000
Shares Issuable Under Options, Granted				9,766,336
Number of shares of common stock available for issuance	456,334			456,334

Stock-Based Awards - Inducement

Stock-Based Awards - Inducement Stock Option Awards (Detail) - 2019 Inducement Plan - shares	Jun. 30, 2021	Dec. 10, 2020	Oct. 29, 2019
Stock-Based Awards
Number of shares of common stock authorized for issuance		1,054,000	500,000
Number of shares of common stock available for issuance	504,251

Stock-Based Awards - Stock-Base

Stock-Based Awards - Stock-Based Compensation (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Stock-based Compensation
Stock-based compensation expense		$ 4,292	$ 1,826	$ 7,378	$ 3,491
Unrecognized stock-based compensation cost	$ 26,106	26,106		26,106
Weighted average period of unrecognized stock-based compensation cost expected to be recognized	3 years 2 months 12 days
Research and Development Expense
Stock-based Compensation
Stock-based compensation expense		1,206	362	1,883	737
Selling and Marketing Expense
Stock-based Compensation
Stock-based compensation expense		1,129	433	1,883	804
General and Administrative Expense
Stock-based Compensation
Stock-based compensation expense		$ 1,957	$ 1,031	$ 3,612	$ 1,950

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - Regeneron - Collaboration Agreement - Maximum $ in Thousands	Oct. 10, 2016USD ($)
Commitments and Contingencies
Reimbursable clinical development costs	$ 25,000
Potential increase in reimbursable clinical development costs	$ 5,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Specialty Pharma
Related Party Transactions
Expenses incurred	$ 29		$ 155
Accounts payable					$ 47
Accrued expenses					0
McCarter | Legal Fees
Related Party Transactions
Expenses incurred		$ 221		$ 512
Accounts payable					47
Accrued expenses					$ 0

Warrants - Additional Informati

Warrants - Additional Information (Detail) - $ / shares	3 Months Ended	6 Months Ended
	Mar. 31, 2021	Jun. 30, 2021	Jan. 29, 2021
Common Stock
Warrants
Common stock issued upon exercise of warrants	11,737	11,737
Common Stock Warrants
Warrants
Number of shares callable by warrants			18,939
Weighted average exercise price to purchase common stock			$ 7.92
Warrants outstanding		0

Common Stock (Details)

Common Stock (Details) - shares	Jun. 30, 2021	Dec. 31, 2020
Common Stock
Common Stock, Shares Authorized	200,000,000	200,000,000

Subsequent Event (Details)

Subsequent Event (Details) $ in Thousands	Aug. 05, 2021USD ($)
Subsequent Event | Collaboration Agreement | Regeneron
Subsequent Events
Maximum amount of reimbursable development costs, no further obligation due to termination of Collaboration Agreement	$ 30,000