Ocular Therapeutix (OCUL) 10-Q 8 May 23 2023 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2023	May 04, 2023
Document And Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
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		77,524,666
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001393434
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 79,026	$ 102,300
Accounts receivable, net	21,124	21,325
Inventory	2,266	1,974
Prepaid expenses and other current assets	4,746	4,028
Total current assets	107,162	129,627
Property and equipment, net	12,022	9,856
Restricted cash	1,764	1,764
Operating lease assets	7,625	8,042
Total assets	128,573	149,289
Current liabilities:
Accounts payable	5,441	5,123
Accrued expenses and other current liabilities	21,993	24,097
Deferred revenue	463	576
Operating lease liabilities	1,818	1,599
Total current liabilities	29,715	31,395
Other liabilities:
Operating lease liabilities, net of current portion	8,114	8,678
Derivative liability	12,914	6,351
Deferred revenue, net of current portion	13,340	13,387
Notes payable, net of discount	25,321	25,257
Other non-current liabilities	100	93
2026 convertible notes, net	29,358	28,749
Total liabilities	118,862	113,910
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 March 31, 2023 and December 31, 2022, respectively
Common stock, $0.0001 par value; 200,000,000 shares authorized and 77,516,638 and 77,201,819 shares issued and outstanding at March 31, 2023 and December 31, 2022, respectively	8	8
Additional paid-in capital	656,863	652,213
Accumulated deficit	(647,160)	(616,842)
Total stockholders' equity	9,711	35,379
Total liabilities and stockholders' equity	$ 128,573	$ 149,289

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
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	77,516,638	77,201,819
Common stock, shares outstanding	77,516,638	77,201,819

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenue:
Total revenue, net	$ 13,374	$ 13,187
Costs and operating expenses:
Cost, Product and Service [Extensible List]	Product	Product
Cost of product revenue	$ 1,214	$ 1,300
Research and development	14,747	13,100
Selling and marketing	10,835	9,063
General and administrative	9,127	7,557
Total costs and operating expenses	35,923	31,020
Loss from operations	(22,549)	(17,833)
Other income (expense):
Interest income	563	18
Interest expense	(1,768)	(1,683)
Change in fair value of derivative liability	(6,563)	6,958
Other expense, net	(1)	(2)
Total other (expense) income, net	(7,769)	5,291
Net loss	$ (30,318)	$ (12,542)
Net loss per share, basic	$ (0.39)	$ (0.16)
Weighted average common shares outstanding, basic	77,386,287	76,745,663
Net loss per share, diluted	$ (0.39)	$ (0.22)
Weighted average common shares outstanding, diluted	77,386,287	82,514,895
Product
Revenue:
Total revenue, net	$ 13,214	$ 12,498
Collaboration revenue
Revenue:
Total revenue, net	$ 160	$ 689

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Total
Balance at Dec. 31, 2021	$ 8	$ 633,795	$ (545,804)	$ 87,999
Balance, shares at Dec. 31, 2021	76,731,940
Stockholders' Equity (Deficit)
Issuance of common stock upon exercise of stock options		129		129
Issuance of common stock upon exercise of stock options, shares	27,674
Stock-based compensation expense		4,209		4,209
Net loss			(12,542)	(12,542)
Balance at Mar. 31, 2022	$ 8	638,133	(558,346)	79,795
Balance, shares at Mar. 31, 2022	76,759,614
Balance at Dec. 31, 2022	$ 8	652,213	(616,842)	35,379
Balance, shares at Dec. 31, 2022	77,201,819
Stockholders' Equity (Deficit)
Issuance of common stock upon exercise of stock options		78		78
Issuance of common stock upon exercise of stock options, shares	26,443
Issuance of common stock upon vesting of restricted stock units (in shares)	288,376
Stock-based compensation expense		4,572		4,572
Net loss			(30,318)	(30,318)
Balance at Mar. 31, 2023	$ 8	$ 656,863	$ (647,160)	$ 9,711
Balance, shares at Mar. 31, 2023	77,516,638

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net loss	$ (30,318)	$ (12,542)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation expense	4,572	4,209
Non-cash interest expense	1,228	1,186
Change in fair value of derivative liability	6,563	(6,958)
Depreciation and amortization expense	483	557
Gain (loss) on disposal of property and equipment	(1)	2
Changes in operating assets and liabilities:
Accounts receivable	201	(2,072)
Prepaid expenses and other current assets	(718)	81
Inventory	(292)	(108)
Accounts payable	1,025	(1,113)
Operating lease assets and liabilities	72	(105)
Accrued expenses	(2,628)	(3,048)
Deferred revenue	(160)	1,311
Net cash used in operating activities	(19,973)	(18,600)
Cash flows from investing activities:
Purchases of property and equipment	(3,379)	(276)
Net cash used in investing activities	(3,379)	(276)
Cash flows from financing activities:
Proceeds from issuance of short-term bridge loan	2,000
Proceeds from exercise of stock options	78	129
Repayment of short-term bridge loan	(2,000)
Net cash provided by financing activities	78	129
Net decrease in cash, cash equivalents and restricted cash	(23,274)	(18,747)
Cash, cash equivalents and restricted cash at beginning of period	104,064	165,928
Cash, cash equivalents and restricted cash at end of period	80,790	147,181
Supplemental disclosure of cash flow information:
Cash paid for interest	701	495
Supplemental disclosure of non-cash investing and financing activities:
Additions to property and equipment included in accounts payable and accrued expenses	$ 646	$ 123

Nature of the Business

Nature of the Business	3 Months Ended
	Mar. 31, 2023
Nature of the Business
Nature of the Business	1. Nature of the Business 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-based formulation technology ELUTYX. The Company’s mission is to build an ophthalmology-focused biopharmaceutical company that capitalizes on the gaps that the Company believes increasingly exist in the ophthalmology sector between single product companies and large, multi-product pharmaceutical companies. 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. The Company is currently commercializing DEXTENZA (dexamethasone insert) 0.4mg, an intracanalicular insert for the treatment of post-surgical ocular inflammation and pain and for the treatment of ocular itching associated with allergic conjunctivitis, in the United States. The Company’s most advanced product candidates are in either Phase 1 or Phase 2 of 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 incurred losses and negative cash flows from operations since its inception, and the Company expects to continue to generate operating losses and negative cash flows from operations in the foreseeable future. As of March 31, 2023, the Company had an accumulated deficit of $647,160. Based on its current operating plan which includes estimates of anticipated cash inflows from product sales and cash outflows from operating expenses and capital expenditures,

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2023
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). The significant accounting policies used in preparation of these unaudited condensed consolidated financial statements are consistent with those described in Note 2 - Summary of Significant Accounting Policies in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, filed with the Securities and Exchange Commission (“SEC”) on March 6, 2023. Use of Estimates The preparation of these unaudited condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of these unaudited condensed consolidated financial statements, and the reported amounts of revenues and expenses during the reporting periods. Significant estimates and assumptions reflected in these unaudited condensed consolidated financial statements include, but are not limited to, the measurement and recognition of reserves for variable consideration related to product sales, revenue recognition related to a collaboration agreement that contains multiple promises, the fair value of derivatives, stock-based compensation, and realizability of net deferred tax assets. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from the Company’s estimates. Unaudited Interim Financial Information The balance sheet at December 31, 2022 was derived from audited consolidated financial statements but does not include all disclosures required by GAAP. The accompanying unaudited condensed consolidated financial statements as of March 31, 2023 and for the three months ended March 31, 2023 and 2022 have been prepared by the Company, pursuant to the rules and regulations of the 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 unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements and the notes thereto for the year ended December 31, 2022 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, filed with the SEC on March 6, 2023. 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 March 31, 2023 and results of operations and cash flows for the three months ended March 31, 2023 and 2022 have been made. The results of operations for the three months ended March 31, 2023 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2023. Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB and adopted by us as of the specified effective date. The Company believes that recently issued accounting pronouncements that are not yet effective will not have a material impact on our consolidated financial statements and disclosures.

Licensing Agreements and Deferr

Licensing Agreements and Deferred Revenue	3 Months Ended
	Mar. 31, 2023
Licensing Agreements and Deferred Revenue
Licensing Agreements and Deferred Revenue	3. Licensing Agreements and Deferred Revenue Incept License Agreement (in-licensing) On September 13, 2018, the Company entered into a second amended and restated license agreement with Incept, LLC (“Incept”) to use and develop certain intellectual property (the “Incept License”). Under the Incept License, as amended and restated, the Company was granted a worldwide, perpetual, exclusive license to use specific Incept technology to develop and commercialize products that are delivered to or around the human eye for diagnostic, therapeutic or prophylactic purposes relating to ophthalmic diseases or conditions. The Company is obligated to pay low single-digit royalties on net sales of commercial products developed using the licensed technology, commencing with the date of the first commercial sale of such products and until the expiration of the last to expire of the patents covered by the license. The terms and conditions of the Incept License are described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, filed with the SEC on March 6, 2023. Royalties paid under this agreement related to product sales were $417 and $369 for the three months ended March 31, 2023 and 2022, respectively. Royalties have been charged to cost of product revenue. AffaMed License Agreement (out-licensing) 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 and for the Company’s OTX-TIC product candidate regarding open-angle glaucoma or ocular hypertension, in each case in mainland China, Taiwan, Hong Kong, Macau, South Korea, and the countries of the Association of Southeast Asian Nations. The Company retains development and commercialization rights for the AffaMed Licensed Products in the rest of the world. The terms and conditions of the License Agreement are described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, filed with the SEC on March 6, 2023. During the three months ended March 31, 2022, the Company invoiced AffaMed $2,000 for a clinical trial support payment in connection with the initiation of the OTX-TIC Phase 2 clinical trial. The Company concluded this clinical support payment was no longer constrained and has allocated the amount to the Phase 2 Clinical Trial of OTX-TIC performance obligation as an addition to deferred revenue. The Company recognized $160 and $689 of collaboration revenue related to this performance obligation for the three months ended March 31, 2023 and 2022, respectively. As of March 31, 2023, the aggregate amount of the transaction price allocated to the partially unsatisfied Phase 2 Clinical Trial of OTX-TIC performance obligation was $803. This amount is expected to be recognized as this performance obligation is satisfied through June 2025. Deferred revenue activity for the three months ended March 31, 2023 was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred Revenue Deferred revenue at December 31, 2022 ​ $ 13,963 Additions ​ ​ — Amounts recognized into revenue ​ ​ (160) Deferred revenue at March 31, 2023 ​ $ 13,803 ​ ​ ​ ​ ​

Cash Equivalents and Restricted

Cash Equivalents and Restricted Cash	3 Months Ended
	Mar. 31, 2023
Cash Equivalents and Restricted Cash
Cash Equivalents and Restricted Cash	4. Cash Equivalents and Restricted Cash As of March 31, 2023 and December 31, 2022, the Company held restricted cash of $1,764, respectively, on its unaudited condensed consolidated balance sheets. The Company held restricted cash as security deposits for its real estate leases. The Company’s unaudited 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 sheets that sum to the total of the same amounts shown in the unaudited condensed consolidated statement of cash flows is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ March 31, ​ 2023 2022 Cash and cash equivalents ​ $ 79,026 ​ $ 145,417 Restricted cash ​ ​ 1,764 ​ ​ 1,764 Total cash, cash equivalents and restricted cash ​ $ 80,790 ​ $ 147,181 ​ ​ ​ ​ ​ ​ ​ ​

Inventory

Inventory	3 Months Ended
	Mar. 31, 2023
Inventory
Inventory	5. Inventory Inventory consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 2022 Raw materials ​ $ 228 ​ $ 309 ​ Work-in-process ​ ​ 773 ​ ​ 899 ​ Finished goods ​ 1,265 ​ 766 ​ ​ ​ $ 2,266 ​ $ 1,974 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Expenses

Expenses	3 Months Ended
	Mar. 31, 2023
Expenses
Expenses	6. Expenses Accrued expenses and other current liabilities consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ 2023 2022 Accrued payroll and related expenses ​ $ 4,527 ​ $ 7,509 Accrued rebates and programs ​ ​ 3,914 ​ ​ 3,560 Accrued professional fees ​ 1,035 ​ 1,228 Accrued research and development expenses ​ 1,947 ​ 1,816 Accrued interest payable on 2026 convertible notes ​ 9,191 ​ 8,756 Accrued other ​ 1,379 ​ 1,228 ​ ​ $ 21,993 ​ $ 24,097 ​

Financial Liabilities

Financial Liabilities	3 Months Ended
	Mar. 31, 2023
Financial Liabilities
Financial Liabilities	7. Financial Liabilities Convertible Notes On March 1, 2019, the Company issued $37,500 of convertible notes, which accrue interest at an annual rate of 6% of their outstanding principal amount, which is payable, along with the principal amount at maturity, on March 1, 2026, unless earlier converted, repurchased or redeemed (the “2026 Convertible Notes”). The Company presents accrued interest in accrued expenses and other current liabilities on the unaudited condensed consolidated balance sheets 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 terms and conditions of the 2026 Convertible Notes are described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, filed with the SEC on March 6, 2023. 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 March 31, 2023 and December 31, 2022 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ 2023 2022 2026 Convertible Notes ​ $ 37,500 ​ $ 37,500 Less: unamortized discount ​ ​ (8,142) ​ ​ (8,751) Total ​ $ 29,358 ​ $ 28,749 ​ 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”). Under the Credit Facility, the Company has a total borrowing capacity of , which was fully drawn down as of March 31, 2023. The carrying value of the Company’s variable interest rate notes payable are recorded at amortized cost, which approximates fair value due to their short-term nature. The terms and conditions of the Credit Agreement and the Credit Facility are described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, filed with the SEC on March 6, 2023, except with respect to Amendment No. 1 to the Credit Agreement as described below. On March 12, 2023, the Company requested, and received, a protective advance of $2,000 under the Credit Agreement as a short-term bridge loan in response to the closure of Silicon Valley Bank by the California Department of Financial Protection and Innovation. This protective advance was deemed a credit extension. The Company repaid the full principal amount of $2,000 in March 2023. On March 31, 2023, the Company entered into Amendment No. 1 to the Credit Agreement (the “Amendment”) to replace the LIBOR-based interest rate provisions of the Credit Agreement with interest rate provisions based on the Secured Overnight Financing Rate, or SOFR, establish a benchmark replacement mechanism and make additional administrative updates. The Company accounted for the Amendment as a modification in accordance with the guidance in ASC 470-50 Debt Borrowings outstanding are as follows : ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, December 31, ​ 2023 2022 Borrowings outstanding ​ $ 25,000 ​ $ 25,000 Accrued exit fee ​ ​ 391 ​ ​ 335 Unamortized discount ​ ​ (70) ​ ​ (78) Long-term notes payable ​ $ 25,321 ​ $ 25,257 ​ As of March 31, 2023, the annual requirement for the repayment of principal for the Credit Facility, inclusive of the final payment of $875 due at expiration, was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ending December 31, Principal Final Payment Total 2023 ​ ​ — ​ ​ — ​ ​ — 2024 ​ ​ 8,333 ​ ​ — ​ ​ 8,333 2025 ​ ​ 16,667 ​ ​ 875 ​ ​ 17,542 ​ ​ $ 25,000 ​ $ 875 ​ $ 25,875 ​

Derivative Liability

Derivative Liability	3 Months Ended
	Mar. 31, 2023
Derivative Liability
Derivative Liability	8. Derivative Liability The 2026 Convertible Notes (Note 7) contain an embedded conversion option that meets the criteria to be bifurcated and accounted for separately from the 2026 Convertible Notes (the "Derivative Liability"). 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 2026 Convertible Notes were initially valued and are remeasured using a "with-and-without" method. The "with-and-without" methodology involves valuing the whole instrument on an as-is basis with the embedded conversion option and then valuing the 2026 Convertible Notes 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. Refer to Note 9 for details regarding the determination of fair value.

Risks and Fair Value

Risks and Fair Value	3 Months Ended
	Mar. 31, 2023
Risks and Fair Value
Risks and Fair Value	9. Risks and Fair Value Concentration of Credit Risk and of Significant Suppliers and Customers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents and accounts receivable. The Company has its cash and cash equivalents balances at two accredited financial institutions, in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. 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 product sales could be adversely affected by a significant interruption in the supply of any of the components of these products. For the three months ended March 31, 2023, three specialty distributor customers accounted for 52%, 25%, and 13% of the Company’s gross product revenue, and at March 31, 2023, three specialty distributor customers accounted for 55%, 24%, and 13% of the Company’s total accounts receivable. No other customer accounted for more than 10% of total revenue for the three months ended March 31, 2023, or accounts receivable at March 31, 2023. For the three months ended March 31, 2022, three specialty distributor customers accounted for 42%, 25%, and 23% of the Company’s gross product revenue. At December 31, 2022, three specialty distributor customers accounted for 52%, 24%, and 15% of the Company’s total accounts receivable. No other customer accounted for more than 10% of total revenue for the three months ended March 31, 2022, or accounts receivable at December 31, 2022. 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 March 31, 2023 and December 31, 2022 and indicate the level of the fair value hierarchy utilized to determine such fair value: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements as of ​ ​ March 31, 2023 Using: ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ Cash equivalents: ​ ​ ​ ​ Money market funds ​ $ 72,796 ​ $ — ​ $ — ​ $ 72,796 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liability: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative liability ​ $ — ​ $ — ​ $ 12,914 ​ $ 12,914 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements as of ​ ​ December 31, 2022 Using: ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ Cash equivalents: ​ ​ ​ ​ Money market funds ​ $ 30,188 ​ $ — ​ $ — ​ $ 30,188 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liability: ​ ​ ​ ​ Derivative liability ​ $ — ​ $ — ​ $ 6,351 ​ $ 6,351 ​ At March 31, 2023, the 2026 Convertible Notes, net of the Derivative Liability, were carried at amortized cost totaling $38,549, comprised of the $29,358 non-current liability (Note 7) and $9,191 accrued interest (Note 6). At December 31, 2022, the 2026 Convertible Notes, net of the Derivative Liability, were carried at amortized cost totaling $37,505, comprised of the $28,749 non-current liability (Note 7) and $8,756 accrued interest (Note 6). The estimated fair value of the 2026 Convertible Notes, without the Derivative Liability, was $34,933 and $33,177 at March 31, 2023 and December 31, 2022, respectively. The fair value of the 2026 Convertible Notes with and without the conversion option is estimated using a binomial lattice approach. The use of this approach requires the use of Level 3 unobservable inputs. The main input when determining the fair value of the 2026 Convertible Notes is the bond yield that pertains to the host instrument without the conversion option. The significant assumption used in determining the bond yield is the market yield movements of a comparable instrument issued as of the valuation date, which is assessed and updated each period. 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 ​ ​ ​ March 31, ​ December 31, ​ ​ ​ 2023 ​ 2022 ​ Company's stock price ​ $ 5.27 ​ $ 2.81 ​ Volatility ​ ​ 76.0 % ​ 93.8 % Bond yield ​ ​ 15.5 % ​ 16.2 % ​ A roll-forward of the derivative liability is as follows: ​ ​ ​ ​ ​ ​ ​ As of Balance at December 31, 2022 ​ $ 6,351 Change in fair value ​ ​ 6,563 Balance at March 31, 2023 ​ $ 12,914 ​

Equity

Equity	3 Months Ended
	Mar. 31, 2023
Equity
Equity	10. Equity On August 9, 2021, the Company and Jefferies LLC (“Jefferies”) entered into an Open Market Sale Agreement (the “2021 Sales Agreement”) under which the Company may offer and sell shares of its common stock having an aggregate offering price of up to $100,000 from time to time through Jefferies, acting as agent. As of May 4, 2023, the Company has

Stock-Based Awards

Stock-Based Awards	3 Months Ended
	Mar. 31, 2023
Stock-Based Awards
Stock-Based Awards	11. Stock-Based Awards For the three months ended March 31, 2023, the Company had three stock-based compensation plans under which it was able to grant stock-based awards, the 2021 Stock Incentive Plan, as amended (the “2021 Plan”), the 2019 Inducement Stock Incentive Plan, as amended (the “2019 Inducement Plan”), and the 2014 Employee Stock Purchase Plan (the “ESPP”), collectively the “Stock Plans”. The terms and conditions of the Stock Plans are described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, filed with the SEC on March 6, 2023. During the three months ended March 31, 2023, the Company granted options to purchase 2,991,141 shares of common stock, at a weighted exercise price of $3.89 per share, all under the 2021 Plan. During the three months ended March 31, 2023, the Company granted 947,633 restricted stock units, or RSUs, all under the 2021 Plan. Each RSU is equivalent to one share of common stock upon vesting. During the three months ended March 31, 2023, a total of 131,347 stock options and RSUs expired or were forfeited. As of March 31, 2023, 2,055,747, 545,375, and 689,475 shares of common stock remained available for issuance under the 2021 Plan, the 2019 Inducement Plan, and the ESPP, respectively. The Company recorded stock-based compensation expense related to stock options and RSUs in the following expense categories of its unaudited condensed consolidated statements of operations and comprehensive loss: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ ​ 2023 2022 Research and development ​ $ 1,141 ​ $ 1,062 ​ Selling and marketing ​ 1,043 ​ 1,138 ​ General and administrative ​ 2,388 ​ 2,009 ​ ​ ​ $ 4,572 ​ $ 4,209 ​ ​ As of March 31, 2023, the Company had an aggregate of $26,118 of unrecognized stock-based compensation cost, which is expected to be recognized over a weighted average period of 2.58 years.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2023
Income Taxes
Income Taxes	12. Income Taxes The Company did not provide for any income taxes in its unaudited condensed consolidated statements of operations and comprehensive loss for the three months ended March 31, 2023 and 2022, respectively. The Company has provided a valuation allowance for the full amount of its net deferred tax assets because, at March 31, 2023 and December 31, 2022, 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.

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2023
Net Loss Per Share
Net Loss Per Share	13. Net Loss Per Share Basic net loss per share was calculated as follows for the three months ended March 31, 2023 and 2022: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2023 ​ 2022 ​ Numerator: ​ ​ ​ ​ ​ ​ Net loss attributable to common stockholders ​ $ (30,318) ​ $ (12,542) ​ Denominator: ​ ​ ​ ​ Weighted average common shares outstanding, basic ​ 77,386,287 ​ 76,745,663 ​ Net loss per share - basic ​ $ (0.39) ​ $ (0.16) ​ ​ For the three months ended March 31, 2023 there was no dilutive impact from potentially issuable common shares. Therefore, diluted net loss per share was the same as basic net loss per share. ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ ​ 2022 Net loss attributable to common stockholders, basic ​ $ (12,542) Interest expense on 2026 Convertible Notes ​ 1,123 Change in fair value of derivative liability ​ ​ (6,958) Net loss attributable to common stockholders, diluted ​ $ (18,377) ​ ​ ​ ​ Weighted average common shares outstanding, basic ​ ​ 76,745,663 Dilutive options (treasury stock method) ​ ​ — Shares issuable upon conversion of 2026 Convertible Notes, as if converted ​ ​ 5,769,232 Weighted average common shares outstanding, diluted ​ 82,514,895 ​ ​ ​ ​ Net loss per share attributable to common stockholders, diluted ​ $ (0.22) ​ The Company excluded the following potentially issuable common shares, outstanding as of March 31, 2023 and 2022, from the computation of diluted net loss per share for the three months ended March 31, 2023 and 2022 because they had an anti-dilutive impact. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2023 2022 Options to purchase common stock ​ ​ 16,546,260 ​ 13,618,221 Restricted stock units ​ ​ 1,708,741 ​ 926,063 Shares issuable upon conversion of 2026 Convertible Notes, if converted ​ ​ 5,769,232 ​ — ​ ​ ​ 24,024,233 ​ 14,544,284 ​

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2023
Commitments and Contingencies.
Commitments and Contingencies	14. Commitments and Contingencies Indemnification Agreements In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless and defend indemnified parties for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third-party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. To date, the Company has not incurred any material costs as a result of such indemnifications.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2023
Related Party Transactions
Related Party Transactions	15. Related Party Transactions The Company has engaged Wilmer Cutler Pickering Hale and Dorr LLP (“WilmerHale”) to provide certain legal services to the Company. The Company's Chief Business Officer’s sister is a managing partner at WilmerHale, who has not participated in providing legal services to the Company. The Company incurred fees for legal services rendered by WilmerHale of approximately $394 and $327 for the three months ended March 31, 2023 and 2022, respectively. As of March 31, 2023 and December 31, 2022, there was $156 and $0 recorded in accounts payable for WilmerHale. As of March 31, 2023 and December 31, 2022, there was $238 and $24 recorded in accrued expenses for WilmerHale.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2023
Subsequent Events
Subsequent Events	16. Subsequent Events No subsequent events noted.

Licensing Agreements and Defe_2

Licensing Agreements and Deferred Revenue (Tables)	3 Months Ended
	Mar. 31, 2023
Licensing Agreements and Deferred Revenue
Schedule of deferred revenue	​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred Revenue Deferred revenue at December 31, 2022 ​ $ 13,963 Additions ​ ​ — Amounts recognized into revenue ​ ​ (160) Deferred revenue at March 31, 2023 ​ $ 13,803 ​ ​ ​ ​ ​

Cash Equivalents and Restrict_2

Cash Equivalents and Restricted Cash (Tables)	3 Months Ended
	Mar. 31, 2023
Cash Equivalents and 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	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ March 31, ​ 2023 2022 Cash and cash equivalents ​ $ 79,026 ​ $ 145,417 Restricted cash ​ ​ 1,764 ​ ​ 1,764 Total cash, cash equivalents and restricted cash ​ $ 80,790 ​ $ 147,181 ​ ​ ​ ​ ​ ​ ​

Inventory (Tables)

Inventory (Tables)	3 Months Ended
	Mar. 31, 2023
Inventory
Components of inventory	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 2022 Raw materials ​ $ 228 ​ $ 309 ​ Work-in-process ​ ​ 773 ​ ​ 899 ​ Finished goods ​ 1,265 ​ 766 ​ ​ ​ $ 2,266 ​ $ 1,974 ​ ​ ​ ​ ​ ​ ​ ​ ​

Expenses (Tables)

Expenses (Tables)	3 Months Ended
	Mar. 31, 2023
Expenses
Schedule of accrued Expenses	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ 2023 2022 Accrued payroll and related expenses ​ $ 4,527 ​ $ 7,509 Accrued rebates and programs ​ ​ 3,914 ​ ​ 3,560 Accrued professional fees ​ 1,035 ​ 1,228 Accrued research and development expenses ​ 1,947 ​ 1,816 Accrued interest payable on 2026 convertible notes ​ 9,191 ​ 8,756 Accrued other ​ 1,379 ​ 1,228 ​ ​ $ 21,993 ​ $ 24,097

Derivatives (Tables)

Derivatives (Tables)	3 Months Ended
	Mar. 31, 2023
Derivative Liability
Summary of roll-forward of the derivative liability	​ ​ ​ ​ ​ ​ ​ As of Balance at December 31, 2022 ​ $ 6,351 Change in fair value ​ ​ 6,563 Balance at March 31, 2023 ​ $ 12,914

Financial Liabilities (Tables)

Financial Liabilities (Tables)	3 Months Ended
	Mar. 31, 2023
Financial Liabilities
Summary of the 2026 Convertible Notes	A summary of the 2026 Convertible Notes at March 31, 2023 and December 31, 2022 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ 2023 2022 2026 Convertible Notes ​ $ 37,500 ​ $ 37,500 Less: unamortized discount ​ ​ (8,142) ​ ​ (8,751) Total ​ $ 29,358 ​ $ 28,749 ​
Schedule of borrowings outstanding	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, December 31, ​ 2023 2022 Borrowings outstanding ​ $ 25,000 ​ $ 25,000 Accrued exit fee ​ ​ 391 ​ ​ 335 Unamortized discount ​ ​ (70) ​ ​ (78) Long-term notes payable ​ $ 25,321 ​ $ 25,257 ​
Schedule of Annual Repayment Requirements for Credit Facility	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ending December 31, Principal Final Payment Total 2023 ​ ​ — ​ ​ — ​ ​ — 2024 ​ ​ 8,333 ​ ​ — ​ ​ 8,333 2025 ​ ​ 16,667 ​ ​ 875 ​ ​ 17,542 ​ ​ $ 25,000 ​ $ 875 ​ $ 25,875

Risks and Fair Value (Tables)

Risks and Fair Value (Tables)	3 Months Ended
	Mar. 31, 2023
Risks and Fair Value
Schedule of assets and liabilities measured at fair Value on recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements as of ​ ​ March 31, 2023 Using: ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ Cash equivalents: ​ ​ ​ ​ Money market funds ​ $ 72,796 ​ $ — ​ $ — ​ $ 72,796 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liability: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative liability ​ $ — ​ $ — ​ $ 12,914 ​ $ 12,914 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements as of ​ ​ December 31, 2022 Using: ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ Cash equivalents: ​ ​ ​ ​ Money market funds ​ $ 30,188 ​ $ — ​ $ — ​ $ 30,188 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liability: ​ ​ ​ ​ Derivative liability ​ $ — ​ $ — ​ $ 6,351 ​ $ 6,351 ​
Schedule of main inputs to valuing the 2026 Convertible Notes with the conversion option	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ ​ March 31, ​ December 31, ​ ​ ​ 2023 ​ 2022 ​ Company's stock price ​ $ 5.27 ​ $ 2.81 ​ Volatility ​ ​ 76.0 % ​ 93.8 % Bond yield ​ ​ 15.5 % ​ 16.2 % ​

Stock-Based Awards (Tables)

Stock-Based Awards (Tables)	3 Months Ended
	Mar. 31, 2023
Stock-Based Awards
Schedule of stock-based compensation expense related to stock options	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ ​ 2023 2022 Research and development ​ $ 1,141 ​ $ 1,062 ​ Selling and marketing ​ 1,043 ​ 1,138 ​ General and administrative ​ 2,388 ​ 2,009 ​ ​ ​ $ 4,572 ​ $ 4,209 ​ ​

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2023
Net Loss Per Share
Schedule of basic and diluted net (loss) income per share attributable to common stockholders	Basic net loss per share was calculated as follows for the three months ended March 31, 2023 and 2022: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2023 ​ 2022 ​ Numerator: ​ ​ ​ ​ ​ ​ Net loss attributable to common stockholders ​ $ (30,318) ​ $ (12,542) ​ Denominator: ​ ​ ​ ​ Weighted average common shares outstanding, basic ​ 77,386,287 ​ 76,745,663 ​ Net loss per share - basic ​ $ (0.39) ​ $ (0.16) ​ ​ For the three months ended March 31, 2023 there was no dilutive impact from potentially issuable common shares. Therefore, diluted net loss per share was the same as basic net loss per share. ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ ​ 2022 Net loss attributable to common stockholders, basic ​ $ (12,542) Interest expense on 2026 Convertible Notes ​ 1,123 Change in fair value of derivative liability ​ ​ (6,958) Net loss attributable to common stockholders, diluted ​ $ (18,377) ​ ​ ​ ​ Weighted average common shares outstanding, basic ​ ​ 76,745,663 Dilutive options (treasury stock method) ​ ​ — Shares issuable upon conversion of 2026 Convertible Notes, as if converted ​ ​ 5,769,232 Weighted average common shares outstanding, diluted ​ 82,514,895 ​ ​ ​ ​ Net loss per share attributable to common stockholders, diluted ​ $ (0.22) ​
Schedule of antidilutive securities, excluded from computation of diluted net loss per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2023 2022 Options to purchase common stock ​ ​ 16,546,260 ​ 13,618,221 Restricted stock units ​ ​ 1,708,741 ​ 926,063 Shares issuable upon conversion of 2026 Convertible Notes, if converted ​ ​ 5,769,232 ​ — ​ ​ ​ 24,024,233 ​ 14,544,284 ​

Nature of the Business and Basi

Nature of the Business and Basis of Presentation - Nature of Business (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Nature of the Business
Accumulated deficit	$ 647,160	$ 616,842
Cash and cash equivalents	$ 79,026	$ 102,300	$ 145,417

Licensing Agreements and Defe_3

Licensing Agreements and Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Collaboration Agreement
Revenue recognized	$ 13,374	$ 13,187
Total deferred revenue:
Deferred revenue, beginning balance	13,963
Amounts recognized into revenue	(160)
Deferred revenue, ending balance	13,803
License Agreement | AffaMed | OTX-TIC Product
Collaboration Agreement
Revenue recognized	160	689
Amount invoiced for initiation of OTX-TIC program		2,000
Transaction price allocated to performance obligations partially unsatisfied	803
License Agreement | Incept
Collaboration Agreement
Royalties paid	$ 417	$ 369

Cash Equivalents and Restrict_3

Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Cash Equivalents and Restricted Cash
Cash and cash equivalents	$ 79,026	$ 102,300	$ 145,417
Restricted cash	1,764	1,764	1,764
Total cash, cash equivalents and restricted cash as shown on the statements of cash flows	$ 80,790	$ 104,064	$ 147,181	$ 165,928

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Inventory
Raw materials	$ 228	$ 309
Work-in-process	773	899
Finished goods	1,265	766
Total inventory	$ 2,266	$ 1,974

Expenses - Summary (Details)

Expenses - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Expenses
Accrued payroll and related expenses	$ 4,527	$ 7,509
Accrued rebates and programs	3,914	3,560
Accrued professional fees	1,035	1,228
Accrued research and development expenses	1,947	1,816
Accrued interest payable on 2026 convertible notes	9,191	8,756
Accrued other	1,379	1,228
Total	$ 21,993	$ 24,097

Financial Liabilities - Convert

Financial Liabilities - Convertible Notes, Other (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 01, 2019
Senior Convertible Notes
Common stock, par value	$ 0.0001	$ 0.0001
2026 Convertible Notes
Senior Convertible Notes
Convertible notes issued	$ 37,500	$ 37,500	$ 37,500
Interest rate (as a percent)			6%
Effective annual interest rate (as a percent)	14.80%

Financial Liabilities - Conve_2

Financial Liabilities - Convertible Notes, Summary (Details) - 2026 Convertible Notes - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 01, 2019
Senior Convertible Notes
Convertible notes	$ 37,500	$ 37,500	$ 37,500
Less: unamortized discount	(8,142)	(8,751)
Convertible notes at amortized cost	$ 29,358	$ 28,749

Financial Liabilities - Notes P

Financial Liabilities - Notes Payable, Additional Information (Details) $ in Thousands	1 Months Ended	3 Months Ended
	Mar. 31, 2023 USD ($)	Mar. 31, 2023 USD ($)
Notes Payable
Protective advance requested under Credit Agreement representing a short-term bridge loan		$ 2,000
Repayment of Protective Advance		2,000
Credit Facility.
Notes Payable
Borrowing capacity under the agreement	$ 25,000	$ 25,000
Protective advance requested under Credit Agreement representing a short-term bridge loan	2,000
Repayment of Protective Advance	$ 2,000

Financial Liabilities - Notes_2

Financial Liabilities - Notes Payable, Borrowings Outstanding (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Notes Payable
Long-term notes payable	$ 25,321	$ 25,257
Credit Facility.
Notes Payable
Borrowings outstanding	25,000	25,000
Accrued exit fee	391	335
Unamortized discount	(70)	(78)
Long-term notes payable	$ 25,321	$ 25,257

Financial Liabilities - Notes_3

Financial Liabilities - Notes Payable, Annual Repayments (Details) - Credit Facility. $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Annual repayment requirements
Credit Facility, Periodic Payment, Principal	$ 25,000
Credit Facility, Final Payment	875
Total	25,875
2024
Annual repayment requirements
Credit Facility, Periodic Payment, Principal	8,333
Total	8,333
2025
Annual repayment requirements
Credit Facility, Periodic Payment, Principal	16,667
Credit Facility, Final Payment	875
Total	$ 17,542

Risks and Fair Value - Concentr

Risks and Fair Value - Concentration of Credit Risk (Details) - Customer - customer	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Total revenue
Concentration risk
Number of major customers	3	3
Total revenue | Customer one
Concentration risk
Concentration risk	52%	42%
Total revenue | Customer two
Concentration risk
Concentration risk	25%	25%
Total revenue | Customer three
Concentration risk
Concentration risk	13%	23%
Accounts receivable
Concentration risk
Number of major customers	3		3
Accounts receivable | Customer one
Concentration risk
Concentration risk	55%		52%
Accounts receivable | Customer two
Concentration risk
Concentration risk	24%		24%
Accounts receivable | Customer three
Concentration risk
Concentration risk	13%		15%

Risks and Fair Value - Fair Val

Risks and Fair Value - Fair Value Measurement (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Liability:
Derivative liability	$ 12,914	$ 6,351
Non-current liability	29,358	28,749
Accrued interest payable on 2026 convertible notes	9,191	8,756
2026 Convertible Notes
Liability:
Convertible debt, amortized cost, including accrued interest	38,549	37,505
Non-current liability	29,358	28,749
Accrued interest payable on 2026 convertible notes	9,191	8,756
Estimated fair value	34,933	33,177
Recurring Basis
Liability:
Derivative liability	12,914	6,351
Money Market Funds | Recurring Basis
Assets:
Cash equivalents	72,796	30,188
Level 1 | Money Market Funds | Recurring Basis
Assets:
Cash equivalents	72,796	30,188
Level 3 | Recurring Basis
Liability:
Derivative liability	$ 12,914	$ 6,351

Risks and Fair Value - Measurem

Risks and Fair Value - Measurement inputs (Details) - 2026 Convertible Notes	Mar. 31, 2023	Dec. 31, 2022
Company's stock price
Derivative Liability
Debt instrument, measurement input	5.27	2.81
Volatility
Derivative Liability
Debt instrument, measurement input	0.760	0.938
Bond yield
Derivative Liability
Debt instrument, measurement input	0.155	0.162

Risks and Fair Value - Derivati

Risks and Fair Value - Derivative Roll-Forward (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Roll forward of the derivative liability
Balance at beginning of period	$ 6,351
Change in fair value	6,563
Balance at end of period	$ 12,914

Equity - Preferred Stock (Detai

Equity - Preferred Stock (Details) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Equity
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Equity - Common Stock (Details)

Equity - Common Stock (Details) - USD ($) $ in Thousands	Aug. 09, 2021	Mar. 31, 2023	Dec. 31, 2022	Nov. 04, 2022
Common Stock
Common stock, shares authorized		200,000,000	200,000,000
Common Stock | 2021 Sales Agreement
Common Stock
Maximum aggregate proceeds from offering	$ 100,000
Number of shares issued				0

Stock-Based Awards - Additional

Stock-Based Awards - Additional Information (Details)	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Stock-Based Awards
Stock options and RSUs expired or were forfeited (in shares)	131,347
2021 Incentive Plan
Stock-Based Awards
Number of shares of common stock available for issuance	2,055,747
2021 Incentive Plan | Common Stock
Stock-Based Awards
Shares issuable under options, granted (in shares)	2,991,141
Exercise price (in dollars per share) | $ / shares	$ 3.89
2019 Inducement Plan
Stock-Based Awards
Number of shares of common stock available for issuance	545,375
2014 Employee Stock Purchase Plan
Stock-Based Awards
Number of shares of common stock available for issuance	689,475
Restricted Stock Units (RSUs) | 2021 Incentive Plan
Stock-Based Awards
Granted (in shares)	947,633

Stock-Based Awards - Stock-Base

Stock-Based Awards - Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Stock-based Compensation
Stock-based compensation expense	$ 4,572	$ 4,209
Unrecognized stock-based compensation cost	$ 26,118
Weighted average period of unrecognized stock-based compensation cost expected to be recognized	2 years 6 months 29 days
Research and Development Expense
Stock-based Compensation
Stock-based compensation expense	$ 1,141	1,062
Selling and Marketing Expense
Stock-based Compensation
Stock-based compensation expense	1,043	1,138
General and Administrative Expense
Stock-based Compensation
Stock-based compensation expense	$ 2,388	$ 2,009

Net (Loss) Income Per Share - B

Net (Loss) Income Per Share - Basic (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Basic net loss per share attributable to common stockholders:
Net loss attributable to common stockholders	$ (30,318)	$ (12,542)
Weighted average common shares outstanding, basic	77,386,287	76,745,663
Net loss per share, basic	$ (0.39)	$ (0.16)

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
	Mar. 31, 2023	Mar. 31, 2022
Reconciliation of net loss attributable to common stockholders for basic and diluted net loss per share
Net loss attributable to common stockholders, basic		$ (12,542)
Interest expense on 2026 Convertible Note		1,123
Change in fair value of derivative liability		(6,958)
Net loss attributable to common stockholders, diluted		$ (18,377)
Weighted average common shares outstanding, basic	77,386,287	76,745,663
Shares issuable upon conversion of 2026 Convertible Note, as if converted		5,769,232
Weighted average common shares outstanding, diluted	77,386,287	82,514,895
Net loss per share attributable to common stockholders, diluted	$ (0.39)	$ (0.22)

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	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total common stock equivalents	24,024,233	14,544,284
Options to Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total common stock equivalents	16,546,260	13,618,221
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total common stock equivalents	1,708,741	926,063
2026 Convertible Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total common stock equivalents	5,769,232

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - WilmerHale - Legal Fees. - Chief Business Officer - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Related Party Transactions
Expenses incurred	$ 394	$ 327
Accounts payable	156		$ 0
Accrued expenses	$ 238		$ 24