Aceragen (ACGN) 10-Q 9 Aug 22 2022 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Aug. 09, 2022
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2022
Entity File Number	001-31918
Entity Registrant Name	IDERA PHARMACEUTICALS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3072298
Entity Address, Address Line One	505 Eagleview Blvd., Suite 212
Entity Address, City or Town	Exton
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19341
City Area Code	484
Local Phone Number	348-1600
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	IDRA
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		53,050,069
Entity Central Index Key	0000861838
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Amendment Flag	false

CONDENSED BALANCE SHEETS

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 24,480	$ 32,545
Prepaid expenses and other current assets	1,111	1,493
Total current assets	25,591	34,038
Property and equipment, net	14	22
Operating lease right-of-use assets	631	734
Other assets	70	70
Total assets	26,306	34,864
Current liabilities:
Accounts payable	148	565
Accrued expenses	4,370	4,088
Operating lease liability	218	209
Total current liabilities	4,736	4,862
Operating lease liability, net of current portion	438	549
Total liabilities	5,174	5,411
Commitments and contingencies (Note 12)
Stockholders' equity:
Common stock, $0.001 par value, Authorized - 140,000 shares; Issued and outstanding - 52,999 and 52,818 at June 30, 2022 and December 31, 2021, respectively	53	53
Additional paid-in capital	766,025	764,861
Accumulated deficit	(744,946)	(735,461)
Total stockholders' equity	21,132	29,453
Total liabilities and stockholders' equity	26,306	34,864
Series A Preferred Stock [Member]
Stockholders' equity:
Preferred stock

CONDENSED BALANCE SHEETS (Paren

CONDENSED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2022	Dec. 31, 2021
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	140,000,000	140,000,000
Common stock, shares issued	52,999,000	52,818,000
Common stock, shares outstanding	52,999,000	52,818,000
Series A Preferred Stock [Member]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares designated	1,500,000	1,500,000
Preferred stock, shares issued	1,000	1,000
Preferred stock, shares outstanding	1,000	1,000

CONDENSED STATEMENTS OF OPERATI

CONDENSED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Operating expenses:
Research and development	$ 2,706	$ 3,893	$ 4,490	$ 10,764
General and administrative	2,659	2,472	5,057	5,628
Restructuring costs		1,192		1,192
Total operating expenses	5,365	7,557	9,547	17,584
Loss from operations	(5,365)	(7,557)	(9,547)	(17,584)
Other income (expense):
Interest income	42	2	45	5
Interest expense		(4)		(7)
Warrant revaluation gain				6,983
Future tranche right revaluation gain				118,803
Foreign currency exchange gain (loss)	16	(4)	17	(25)
Net income (loss)	(5,307)	(7,563)	(9,485)	108,175
Net income (loss) applicable to common stockholders (Note 11)
- Basic	(5,307)	(7,563)	(9,485)	105,450
- Diluted	$ (5,307)	$ (7,563)	$ (9,485)	$ (17,611)
Net income (loss) per share applicable to common stockholders (Note 11)
- Basic	$ (0.10)	$ (0.15)	$ (0.18)	$ 2.31
- Diluted	$ (0.10)	$ (0.15)	$ (0.18)	$ (0.32)
Weighted-average number of common shares used in computing net income (loss) per share applicable to common stockholders
- Basic	52,972	49,909	52,933	45,575
- Diluted	52,972	49,909	52,933	54,937

CONDENSED STATEMENTS OF CASH FL

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash Flows from Operating Activities:
Net income (loss)	$ (9,485)	$ 108,175
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Stock-based compensation	1,107	1,515
Warrant liability revaluation gain		(6,983)
Future tranche right liability revaluation gain		(118,803)
Issuance of common stock for services rendered	44	130
Accretion of discounts on short-term investments		(1)
Depreciation and amortization expense	8	11
Changes in operating assets and liabilities:
Prepaid expenses and other assets	382	742
Accounts payable, accrued expenses, and other liabilities	(150)	(640)
Other	1	4
Net cash used in operating activities	(8,093)	(15,850)
Cash Flows from Investing Activities:
Proceeds from maturity of available-for-sale securities		4,500
Net cash provided by investing activities		4,500
Cash Flows from Financing Activities:
Proceeds from common stock financings, net		18,841
Proceeds from employee stock purchases	28	34
Proceeds from exercise of common stock options and warrants		271
Payments on seller-financed purchases		(435)
Net cash provided by financing activities	28	18,711
Net increase (decrease) in cash and cash equivalents	(8,065)	7,361
Cash and cash equivalent, beginning of period	32,545	33,229
Cash and cash equivalents, end of period	24,480	40,590
Supplemental disclosure of cash flow information:
Cash paid for interest		5
Supplemental disclosure of non-cash financing and investing activities:
Offering costs in accounts payable and accrued expenses	$ 15	$ 68

CONDENSED STATEMENTS OF REDEEMA

CONDENSED STATEMENTS OF REDEEMABLE PREFERRED STOCK AND STOCKHOLDERS' DEFICIT - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Series B1 Redeemable Convertible Preferred Stock	Total
Beginning balance at Dec. 31, 2020	$ 38	$ 742,342	$ (833,552)		$ (91,172)
Beginning balance (in shares) at Dec. 31, 2020	38,291,000			24,000
Sale of common stock, net of issuance costs	$ 3	16,258			16,261
Sale of common stock, net of issuance costs (in shares)	3,195,000
Conversion of Series B1 preferred stock	$ 1	(1)
Conversion of Series B1 preferred stock (in shares)	1,415,000			(14,000)
Issuance of common stock under employee stock purchase plan		28			28
Issuance of common stock under employee stock purchase plan (in shares)	8,000
Issuance of common stock under equity incentive plan (vesting of restricted stock units) (in shares)	237,000
Issuance of common stock upon exercise of common stock options and warrants	$ 4	267			271
Issuance of common stock upon exercise of common stock options and warrants (in shares)	3,375,000
Issuance of common stock for services rendered		67			67
Issuance of common stock for services rendered (in shares)	16,000
Stock-based compensation expense		1,111			1,111
Net income (loss)			115,738		115,738
Ending balance at Mar. 31, 2021	$ 46	760,072	(717,814)		42,304
Ending balance (in shares) at Mar. 31, 2021	46,537,000			10,000
Beginning balance at Dec. 31, 2020	$ 38	742,342	(833,552)		(91,172)
Beginning balance (in shares) at Dec. 31, 2020	38,291,000			24,000
Conversion of Series B1 preferred stock (in shares)				(23,684)
Net income (loss)					108,175
Ending balance at Jun. 30, 2021	$ 52	763,051	(725,377)		37,726
Ending balance (in shares) at Jun. 30, 2021	52,115,000
Beginning balance at Mar. 31, 2021	$ 46	760,072	(717,814)		42,304
Beginning balance (in shares) at Mar. 31, 2021	46,537,000			10,000
Sale of common stock, net of issuance costs	$ 2	2,510			2,512
Sale of common stock, net of issuance costs (in shares)	2,076,000
Conversion of Series B1 preferred stock	$ 1	(1)
Conversion of Series B1 preferred stock (in shares)	953,000			(10,000)
Issuance of common stock under employee stock purchase plan		6			6
Issuance of common stock under employee stock purchase plan (in shares)	6,000
Issuance of common stock upon exercise of common stock options and warrants	$ 3	(3)
Issuance of common stock upon exercise of common stock options and warrants (in shares)	2,496,000
Issuance of common stock for services rendered		63			63
Issuance of common stock for services rendered (in shares)	47,000
Stock-based compensation expense		404			404
Net income (loss)			(7,563)		(7,563)
Ending balance at Jun. 30, 2021	$ 52	763,051	(725,377)		37,726
Ending balance (in shares) at Jun. 30, 2021	52,115,000
Beginning balance at Dec. 31, 2021	$ 53	764,861	(735,461)		$ 29,453
Beginning balance (in shares) at Dec. 31, 2021	52,818,000				52,818,000
Sale of common stock, net of issuance costs		(15)			$ (15)
Issuance of common stock under employee stock purchase plan		16			16
Issuance of common stock under employee stock purchase plan (in shares)	42,000
Issuance of common stock under equity incentive plan (vesting of restricted stock units) (in shares)	27,000
Issuance of common stock for services rendered		22			22
Issuance of common stock for services rendered (in shares)	37,000
Stock-based compensation expense		545			545
Net income (loss)			(4,178)		(4,178)
Ending balance at Mar. 31, 2022	$ 53	765,429	(739,639)		25,843
Ending balance (in shares) at Mar. 31, 2022	52,924,000
Beginning balance at Dec. 31, 2021	$ 53	764,861	(735,461)		$ 29,453
Beginning balance (in shares) at Dec. 31, 2021	52,818,000				52,818,000
Net income (loss)					$ (9,485)
Ending balance at Jun. 30, 2022	$ 53	766,025	(744,946)		$ 21,132
Ending balance (in shares) at Jun. 30, 2022	52,999,000				52,999,000
Beginning balance at Mar. 31, 2022	$ 53	765,429	(739,639)		$ 25,843
Beginning balance (in shares) at Mar. 31, 2022	52,924,000
Issuance of common stock under employee stock purchase plan		12			12
Issuance of common stock under employee stock purchase plan (in shares)	34,000
Issuance of common stock for services rendered		22			22
Issuance of common stock for services rendered (in shares)	41,000
Stock-based compensation expense		562			562
Net income (loss)			(5,307)		(5,307)
Ending balance at Jun. 30, 2022	$ 53	$ 766,025	$ (744,946)		$ 21,132
Ending balance (in shares) at Jun. 30, 2022	52,999,000				52,999,000

Business and Organization

Business and Organization	6 Months Ended
	Jun. 30, 2022
Business and Organization
Business and Organization	Note 1. Business and Organization ​ Business Overview ​ Idera Pharmaceuticals, Inc. (“Idera” or the “Company”), a Delaware corporation, is a biopharmaceutical company with a business strategy focused on the clinical development, and ultimately the commercialization, of drug candidates for rare disease indications characterized by small, well-defined patient populations with serious unmet medical needs. The Company’s current focus is to identify and potentially acquire rights to novel development and commercial stage rare disease programs through new business development opportunities, including additional strategic alternatives. The Company has in the past and may in the future explore collaborative alliances to support development and commercialization of any of our drug candidates. ​ Until December 2021, the Company was developing tilsotolimod, via intratumoral injection, for the treatment of solid tumors in combination with nivolumab, an anti-PD1 antibody marketed as Opdivo® by Bristol Myers Squibb Company (“BMS”), and/or ipilimumab, an anti-CTLA4 antibody marketed as Yervoy® by BMS. Due to Phase 3 results in anti-PD-1 refractory advanced melanoma, reported in March 2021, which showed the study failed to meet its primary endpoint, as well as a decision in December 2021 to discontinue enrollment in ILLUMINATE-206, the Company’s Phase 2 study in solid tumors, Company-sponsored development of tilsotolimod has been discontinued. ​ Although clinical trials with tilsotolimod have not yet translated into a new treatment alternative for patients, the Company believes that data supporting tilsotolimod’s mechanism of action and encouraging safety profile from across the array of pre-clinical and clinical work to date, together with its intellectual property protection, are noteworthy. As a result, in December 2021, the Company announced it would consider, and continues to consider, an out-licensing arrangement so that tilsotolimod’s full potential might continue to be explored on behalf of patients who did not respond to traditional immunotherapy. ​ Reduction-in-Force ​ In the second quarter of 2021, following the announcement that the Company’s ILLUMINATE-301 trial did not meet its primary endpoint of objective response rate (“ORR”), the Company implemented a reduction in force which affected approximately 50% of its workforce. Sixteen positions were eliminated, primarily in the area of research and development. Reduction-in-force was undertaken in order to align the Company’s workforce with its needs in light of the outcome of ILLUMINATE-301’s ORR endpoint and other business development activities focused on identifying new portfolio opportunities. ​ In connection with these actions, the Company incurred and paid one-time termination costs for the reduction in workforce, which includes severance, benefits and related costs, of approximately $1.2 million during the second quarter of 2021. ​ Nasdaq Compliance ​ As previously disclosed in the Current Report on Form 8-K filed with the SEC on December 1, 2021, on November 26, 2021, Idera received a deficiency letter from the Nasdaq Listing Qualifications Department (the “Staff”) of The Nasdaq Stock Market, LLC (“Nasdaq”), notifying the Company that it is not in compliance with Nasdaq Listing Rule 5550(a)(2), which requires the Company to maintain a minimum bid price of at least $1 per share for continued listing on The Nasdaq Capital Market (the “Minimum Bid Requirement”). Note 1. Business and Organization (Continued) ​ On May 26, 2022, the Company received notice (the “Nasdaq Notice”) from the Staff indicating that, while the Company has not regained compliance with the Minimum Bid Requirement, the Staff has determined that the Company is eligible for an additional 180-day period, or until November 21, 2022, to regain compliance. If at any time during this second 180-day compliance period, the closing bid price of the Company’s common stock is at least $1 per share for a minimum of ten consecutive business days, the Staff will provide the Company with written confirmation of compliance. If compliance cannot be demonstrated by November 21, 2022, the Staff will provide written notification that the Company’s common stock will be subject to delisting. The Company would then be entitled to appeal the Staff’s determination to a Nasdaq hearings panel. The Company intends to monitor the closing bid price of its common stock and consider implementing available options to regain compliance with the Minimum Bid Requirement. ​ Liquidity and Financial Condition ​ As of June 30, 2022, the Company had an accumulated deficit of $744.9 million and a cash and cash equivalents balance of $24.5 million. The Company expects to incur substantial operating losses in future periods and will require additional capital as it seeks to advance any future drug candidates through development to commercialization and/or continues to pursue strategic alternatives or additional collaborations. The Company does not expect to generate product revenue, sales-based milestones, or royalties until the Company successfully completes development of and obtains marketing approval for any future drug candidates, either alone or in collaboration with third parties. To commercialize any future drug candidates, the Company and/or a third-party partner must complete clinical development and comply with comprehensive regulatory requirements. The Company is subject to numerous risks and uncertainties similar to those of other companies of the same size within the biotechnology industry, such as uncertainty of clinical trial outcomes, uncertainty of additional funding and/or successful strategic partnerships or collaborations, and history of operating losses. ​ The Company follows the provisions of Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 205-40, Presentation of Financial Statements—Going Concern ​

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2022
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	Note 2. Summary of Significant Accounting Policies ​ Basis of Presentation ​ The accompanying unaudited financial statements included herein have been prepared by the Company in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to the rules and regulations of the SEC. Accordingly, 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. In the opinion of management, all adjustments, consisting of normal recurring adjustments, and disclosures considered necessary for a fair presentation of interim period results have been included. Interim results for the three and six months ended June 30, 2022 are not necessarily indicative of results that may be expected for the year ending December 31, 2022. For further information, refer to the financial statements and footnotes thereto included in the Company’s 2021 Form 10-K. ​ Cash and Cash Equivalents ​ The Company considers all highly liquid investments with maturities of 90 days or less when purchased to be “cash equivalents.” Cash and cash equivalents at June 30, 2022 and December 31, 2021 consisted of cash and money market funds. ​ Financial Instruments ​ The fair value of the Company’s financial instruments is determined and disclosed in accordance with the three-tier fair value hierarchy specified in Note 3. The Company is required to disclose the estimated fair values of its financial instruments. As of June 30, 2022 and December 31, 2021, the Company’s financial instruments consisted of cash and cash equivalents. The estimated fair values of these financial instruments approximate their carrying values. As of June 30, 2022, the Company did not have any derivatives, hedging instruments or other similar financial instruments. ​ Concentration of Credit Risk ​ Financial instruments that subject the Company to credit risk primarily consist of cash and cash equivalents. The Company’s credit risk is managed by investing in highly rated money market instruments, U.S. treasury bills, corporate bonds, commercial paper and/or other debt securities. Due to these factors, no significant additional credit risk is believed by management to be inherent in the Company’s assets. As of June 30, 2022, all the Company’s cash and cash equivalents were held at two financial institutions. ​ Operating Lease Right-of-use Assets and Lease Liability ​ The Company accounts for leases under ASC 842, Leases. Operating leases are included in “Operating lease right-of-use assets” within the Company’s balance sheets and represent the Company’s right to use an underlying asset for the lease term. The Company’s related obligation to make lease payments are included in “Operating lease liability” and “Operating lease liability, net of current portion” within the Company’s balance sheets. Operating lease right-of-use (“ROU”) assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rates, which are the rates incurred to borrow on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The ROU assets are tested for impairment according to ASC 360, Property, Plant, and Equipmen ​ As of June 30, 2022 and December 31, 2021, the Company’s operating lease ROU assets and corresponding short-term and long-term lease liabilities primarily relate to its existing Exton, PA facility operating lease which expires on May 31, 2025. ​ Note 2. Summary of Significant Accounting Policies (Continued) ​ Warrant Liability ​ The Company accounts for stock warrants as either equity instruments, liabilities or derivative liabilities in accordance with ASC 480, Distinguishing Liabilities from Equity Derivatives and Hedging , depending on the specific terms of the warrant agreement. Freestanding warrants for shares that are potentially redeemable, whereby the Company may be required to transfer assets (e.g. cash or other assets) outside of its control, are classified as liabilities. Liability-classified warrants are recorded at their estimated fair values at each reporting period until they are exercised, terminated, reclassified or otherwise settled. Changes in the estimated fair value of liability-classified warrants are recorded in Warrant Revaluation Gain (Loss) in the Company’s condensed statements of operations. Equity classified warrants are recorded within additional paid-in capital at the time of issuance and not subject to remeasurement. During the three months ended March 31, 2021, all of the Company’s liability-classified warrants terminated and, accordingly, the liability balance was derecognized. ​ Future Tranche Right Liability ​ On December 23, 2019, the Company entered into a Securities Purchase Agreement (the “December 2019 Securities Purchase Agreement”) with institutional investors affiliated with Baker Brothers, an existing stockholder (see Note 10). As more fully described in Note 6, the December 2019 Securities Purchase Agreement contained call options on redeemable preferred shares with warrants (conditionally exercisable for shares that are puttable). The Company determined that these call options represented freestanding financial instruments and accounted for the options as liabilities (“Future Tranche Right Liability”) under ASC 480, which requires the measurement and recognition of the fair value of the liability at the time of issuance and at each reporting period. Any change in fair value was recognized in Future Tranche Right Liability Revaluation Gain (Loss) in the Company’s condensed statements of operations. During the three months ended March 31, 2021, the liability-classified call options provided for under the December 2019 Securities Purchase Agreement terminated and, accordingly, the liability balance was derecognized. ​ Preferred Stock ​ The Company applies ASC 480 when determining the classification and measurement of its preferred stock. Preferred shares subject to mandatory redemption are classified as liability instruments and are measured at fair value. Conditionally redeemable preferred shares (including preferred shares that feature redemption rights that are either within the control of the holder or subject to redemption upon the occurrence of uncertain events not solely within the Company’s control) are classified as temporary equity. At all other times, preferred shares are classified as stockholders’ equity. ​ Accretion of redeemable convertible preferred stock includes the accretion of the Company's Series B redeemable convertible preferred stock to its stated value. The carrying value of the Series B redeemable convertible preferred stock is accreted to redemption value using the effective interest method, from the date of issuance to the earliest date the holders can demand redemption or until the redeemable convertible preferred stock cease to be outstanding. ​ Income Taxes ​ In accordance with ASC 270, Interim Reporting Income Taxes Note 2. Summary of Significant Accounting Policies (Continued) ​ New Accounting Pronouncements ​ From time to time, new accounting pronouncements are issued by the FASB and rules are issued by the SEC that the Company has or will adopt as of a specified date. Unless otherwise noted, management does not believe that any other recently issued accounting pronouncements issued by the FASB or guidance issued by the SEC had, or is expected to have, a material impact on the Company’s present or future financial statements. ​ Recently Adopted Accounting Pronouncements ​ In August 2020, the FASB issued Accounting Standard Update (“ASU”) No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”), which simplifies the guidance on an issuer’s accounting for convertible instruments and contracts in its own equity. The Company adopted ASU 2020-06 in the first quarter of 2021. The adoption of ASU 2020-06 did not have a material effect on the Company’s financial statements.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2022
Fair Value Measurements
Fair Value Measurements	Note 3. Fair Value Measurements ​ Assets and Liabilities Measured at Fair Value on a Recurring Basis ​ The Company applies the guidance in ASC 820, Fair Value Measurement ​ The Company uses a fair value hierarchy, which distinguishes between assumptions based on market data (observable inputs) and an entity's own assumptions (unobservable inputs). The guidance requires that fair value measurements be classified and disclosed in one of the following three categories: ● Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; ● Level 2: Quoted prices in markets that are not active or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability; or ● Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). ​ Determining which category an asset or liability falls within the hierarchy requires significant judgment. The Company evaluates its hierarchy disclosures each reporting period. There were no transfers between Level 1 , 2 , and 3 during the six months ended June 30, 2022. ​ ​ Note 3. Fair Value Measurements (Continued) ​ The table below presents the assets and liabilities measured and recorded in the financial statements at fair value on a recurring basis at June 30, 2022 and December 31, 2021 categorized by the level of inputs used in the valuation of each asset and liability. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2022 (In thousands) ​ Total ​ Level 1 ​ Level 2 ​ Level 3 Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash ​ $ 250 ​ $ 250 ​ $ — ​ $ — ​ Cash equivalents – money market funds ​ ​ 24,230 ​ ​ 24,230 ​ ​ — ​ ​ — ​ Total assets ​ $ 24,480 ​ $ 24,480 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ (In thousands) ​ Total ​ Level 1 ​ Level 2 ​ Level 3 ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash ​ $ 250 ​ $ 250 ​ $ — ​ $ — ​ Cash equivalents – money market funds ​ ​ 32,295 ​ ​ 32,295 ​ ​ — ​ ​ — ​ Total assets ​ $ 32,545 ​ $ 32,545 ​ $ — ​ $ — ​ ​ The Level 1 assets consist of money market funds, which are actively traded daily. ​ Changes in Level 3 Liabilities Measured at Fair Value on a Recurring Basis ​ Warrant Liability and Future Tranche Right Liability ​ The reconciliation of the Company's warrant and future tranche right liability measured at fair value on a recurring basis using unobservable inputs (Level 3) is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Future ​ ​ Warrant ​ Tranche Right (In thousands) ​ Liability ​ Liability Balance, December 31, 2020 $ 6,983 ​ $ 118,803 Change in the fair value of liability (1) (6,983) ​ (118,803) Balance, June 30, 2021 $ — ​ $ — (1) During the six months ended June 30, 2021, the Company’s liability-classified warrants and future tranche rights terminated, and accordingly, the liabilities were derecognized.

Property and Equipment

Property and Equipment	6 Months Ended
	Jun. 30, 2022
Property and Equipment
Property and Equipment	Note 4. Property and Equipment ​ At June 30, 2022 and December 31, 2021, property and equipment, net, consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ (In thousands) 2022 2021 Leasehold improvements ​ $ 107 ​ $ 107 ​ Equipment and other ​ 712 ​ 712 ​ Total property and equipment, at cost ​ $ 819 ​ $ 819 ​ Less: Accumulated depreciation and amortization ​ 805 ​ 797 ​ Property and equipment, net ​ $ 14 ​ $ 22 ​ ​ ​ Depreciation and amortization expense on property and equipment was less than $0.1 million for each of the three and six months ended June 30, 2022 and 2021. Additionally, there were

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2022
Accrued Expenses
Accrued Expenses	Note 5. Accrued Expenses ​ At June 30, 2022 and December 31, 2021, accrued expenses consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, (In thousands) ​ 2022 2021 Payroll and related costs ​ $ 706 ​ $ 477 ​ Clinical and nonclinical trial expenses ​ 2,984 ​ 2,909 ​ Professional and consulting fees ​ 587 ​ 591 ​ Other ​ 93 ​ 111 ​ Total accrued expenses ​ $ 4,370 ​ $ 4,088 ​ ​

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock	6 Months Ended
	Jun. 30, 2022
Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock	Note 6. Redeemable Convertible Preferred Stock ​ December 2019 Private Placement ​ On December 23, 2019, the Company entered into the December 2019 Securities Purchase Agreement, under which the Company sold 23,684 shares of Series B1 convertible preferred stock (“Series B1 Preferred Stock”) and warrants to purchase 2,368,400 shares of the Company’s common stock at an exercise price of $1.52 per share (or, if the holder elected to exercise the warrants for shares of Series B1 Preferred Stock, 23,684 shares of Series B1 Preferred Stock at an exercise price of $152 per share) for aggregate gross proceeds of $3.9 million (the “Initial Closing”). ​ In addition, the Company agreed to sell to the purchasers, at their option and subject to certain conditions, (i) 98,685 shares of Series B2 convertible preferred stock (“Series B2 Preferred Stock”) and 9,868,500 warrants to purchase common stock at an exercise price of $1.52 per share (or, at the election of the holder, 98,685 shares of Series B2 Preferred Stock at an price of $152 per share), for aggregate gross proceeds of $15 million (the “Series B2 Tranche”), (ii) 82,418 shares of Series B3 convertible preferred stock (“Series B3 Preferred Stock”) and 6,593,440 warrants to purchase common stock at an exercise price of $1.82 per share (or, at the election of the holder, 65,934 shares of Series B3 Preferred Stock at a price of $182 per share), for aggregate gross proceeds of $15 million (the “Series B3 Tranche”), and (iii) 82,418 shares of Series B4 convertible preferred stock (“Series B4 Preferred Stock”) and 6,593,440 warrants to purchase common stock at an exercise price of $1.82 per share (or, at the election of the holder, 65,934 shares of Series B3 Preferred Stock at a price of $182 per share), for aggregate gross proceeds of $15 million (the “Series B4 Tranche”) over a period of up to 21 months following the Company’s 2020 Annual Meeting of Stockholders held on May 12, 2020, where stockholders of the Company voted to approve an amendment to the Company’s Restated Certificate of Incorporation to increase the authorized number of shares of the Company’s common stock to 140,000,000 . As consideration for the future tranche rights, the Company received aggregate gross proceeds of $6.2 million in December 2019. ​ The purchase and sale of the securities issuable under the Series B2, B3, and B4 tranches described above were subject to three separate closings, each to be conducted at the purchasers’ discretion. The right of the purchasers to purchase Series B2, Series B3, and Series B4 Preferred Stock was set to expire on the 10th business day following the Company’s ORR Data Announcement (as defined in the for its ILLUMINATE-301 study. ​ Accounting Considerations ​ The Company determined that the Series B1 Preferred Stock, the accompanying Series B1 warrants, and each of the future tranche rights represent freestanding financial instruments. The Series B1 warrants and the future tranche rights were classified as liabilities until their termination in March 2021 as the underlying shares were potentially redeemable and such redemption was deemed to be outside of the Company’s control. ​ Due to the redeemable nature of the Series B1 Preferred Stock, the Series B1 Preferred Stock was classified as temporary equity and the carrying value was being accreted to its redemption value as of December 31, 2020 and while the Series B1 Preferred Stock was outstanding during 2021. During the six months ended June 30, 2021, all the Company’s 23,684 shares of Series B1 Preferred Stock outstanding were converted into shares of the Company’s common stock. See Note 10 for details. For the three and six months ended June 30, 2022 and 2021, accretion was de minimis.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2022
Stockholders' Equity
Stockholders' Equity	Note 7. Stockholders’ Equity ​ Equity Financings ​ Common Stock Purchase Agreement ​ On March 4, 2019, the Company entered into a Purchase Agreement with Lincoln Park Capital Fund, LLC (“Lincoln Park”), which was amended on September 2, 2020 (as amended to date, the “LPC Purchase Agreement”), pursuant to which, upon the terms and subject to the conditions and limitations set forth therein, Lincoln Park committed to purchase an aggregate of $35.0 million of shares of Company common stock from time to time at the Company’s sole discretion over a 36-month period (the “Purchase Period”). As consideration for entering into the LPC Purchase Agreement, the Company issued 269,749 shares of its common stock to Lincoln Park as a commitment fee (the “Commitment Shares”). The closing price of the Company’s common stock on March 4, 2019 was $2.84 and the Company did not receive any cash proceeds from the issuance of the Commitment Shares. ​ During the six months ended June 30, 2022, the Company did not sell any shares under the LPC Purchase Agreement. The Purchase Period expired on March 4, 2022. Accordingly, the Company no longer has access to additional capital under the LPC Purchase Agreement. ​ During the six months ended June 30, 2021, the Company sold 800,000 shares of common stock, pursuant to the LPC Purchase Agreement, resulting in net proceeds of $4.2 million. ​ "At-The-Market" Equity Program ​ In November 2018, the Company entered into an Equity Distribution Agreement (the “ATM Agreement”) with JMP Securities LLC (“JMP”) pursuant to which the Company may issue and sell shares of its common stock having an aggregate offering price of up to $50.0 million (the “Shares”) through JMP as its agent. Subject to the terms and conditions of the ATM Agreement, JMP will use commercially reasonable efforts to sell the Shares from time to time, based upon the Company’s instructions, by methods deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended, or if specified by the Company, by any other method permitted by law, including but not limited to in negotiated transactions. The Company has no obligation to sell any of the Shares, and the Company or JMP may at any time suspend sales under the ATM Agreement or terminate the ATM Agreement. JMP is entitled to a fixed commission of 3.0% of the gross proceeds from Shares sold. ​ During the six months ended June 30, 2022, the Company sold no Shares pursuant to the ATM Agreement. ​ During the six months ended June 30, 2021, the Company sold 4,470,593 Shares pursuant to the ATM Agreement, resulting in net proceeds, after deduction of commissions and other offering expenses, of $14.6 million. As of June 30, 2022, the Company may sell up to an additional $19.5 million of Shares under the ATM Agreement, subject to applicable securities laws and related rules and regulations. ​ ​ Note 7. Stockholders’ Equity (Continued) ​ April 2020 Private Placement ​ On April 7, 2020, the Company entered into a Securities Purchase Agreement with Pillar Partners Foundation, L.P. (“Pillar Partners”), a related party as more fully described in Note 10, which was amended on December 11, 2020 (as amended to date, the “April 2020 Securities Purchase Agreement”), under which the Company sold 3,039,514 shares of common stock and accompanying warrants to purchase 3,039,514 shares of the Company’s common stock with an exercise price of $2.28 per share, for aggregate gross proceeds of $5.0 million. Each share and the accompanying warrant had a combined purchase price of $1.645, which included $0.125 for each share of common stock underlying each warrant. The April 2020 Securities Purchase Agreement also provided for the option for Pillar Partners to purchase 2,747,252 shares of the Company’s common stock (or pre-funded warrants to purchase shares of the Company’s common stock at an exercise price of $0.01 in lieu of certain shares to the extent that purchasing such shares will cause Pillar Investment Entities (as defined below) to beneficially own in excess of 19.99% of the total number of shares of common stock outstanding post-transaction) and warrants to purchase up to 1,373,626 shares of the Company’s common stock (with an exercise price of $2.71), for aggregate gross proceeds of $5.0 million (the “April 2020 Private Placement Second Closing”). Subsequently, in December 2020, the April 2020 Private Placement Second Closing was consummated. Total net proceeds received pursuant to the April 2020 Securities Purchase Agreement, after deduction of offering expenses, was $9.8 million. ​ July 2020 Private Placement On July 13, 2020, the Company entered into a Securities Purchase Agreement (the “July 2020 Securities Purchase Agreement”) with Pillar Partners Foundation, L.P. (“Pillar Partners”) at their sole discretion, pre-funded warrants to purchase up to 784,615 shares of the Company’s common stock, at an exercise price of $0.01 per share, and warrants to purchase up to 274,615 shares of the Company’s common stock, at an exercise price of $9.75 , for aggregate gross proceeds of $5.1 million (the “July 2020 Private Placement Second Closing”). ​ Common Stock Warrants ​ In connection with various financing transactions, the Company has issued warrants to purchase shares of the Company’s common stock and preferred stock. The Company accounts for common and preferred stock warrants as equity instruments or liabilities, depending on the specific terms of the warrant agreement. ​ Note 7. Stockholders’ Equity (Continued) ​ The following table summarizes outstanding warrants to purchase shares of the Company’s common stock and/or preferred stock as of June 30, 2022 and December 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of Shares ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ Weighted-Average ​ ​ ​ Description ​ 2022 ​ 2021 ​ Exercise Price ​ Expiration Date ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity-classified Warrants ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ May 2013 warrants 15,437 ​ 15,437 ​ ​ $ 0.08 ​ None ​ September 2013 warrants 4,096 ​ 4,096 ​ ​ $ 0.08 ​ None ​ February 2014 warrants 2,171 ​ 2,171 ​ ​ $ 0.08 ​ None ​ April 2020 Private Placement first closing warrants ​ 3,039,514 ​ 3,039,514 ​ ​ $ 2.28 ​ Apr 2023 ​ April 2020 Private Placement second closing warrants ​ 1,373,626 ​ 1,373,626 ​ ​ $ 2.71 ​ Dec 2023 ​ April 2020 Private Placement second closing warrants ​ 1,143,428 ​ 1,143,428 ​ ​ $ 0.01 ​ None ​ July 2020 Private Placement first closing warrants ​ 389,731 ​ 389,731 ​ ​ $ 0.01 ​ None ​ July 2020 Private Placement first closing warrants ​ 2,764,227 ​ 2,764,227 ​ ​ $ 2.58 ​ Jul 2023 ​ ​ ​ 8,732,230 ​ 8,732,230 ​ ​ ​ ​ ​ ​ Total outstanding 8,732,230 ​ 8,732,230 ​ ​ ​ ​ ​ ​ ​

Collaboration and License Agree

Collaboration and License Agreements	6 Months Ended
	Jun. 30, 2022
Collaboration and License Agreements
Collaboration and License Agreements	Note 8. Collaboration and License Agreements ​ Scriptr Collaboration and Option Agreement ​ In February 2021, the Company entered into a collaboration and option agreement with Scriptr Global, Inc. (“Scriptr”), pursuant to which (i) the Company and Scriptr conduct a research collaboration utilizing Scriptr Platform Technology (“SPT”) to identify, research and develop gene therapy candidates (each, a “Collaboration Candidate”) for the treatment, palliation, diagnosis or prevention of (a) myotonic dystrophy type 1 (“DM1 Field”) and (b) Friedreich’s Ataxia (“FA Field”) on a Research Program-by-Research Program (as defined below) basis, as applicable, and (ii) the Company was granted an exclusive option, in its sole discretion, to make effective the Scriptr License Agreement, as defined below, for a given Research Program, as defined below, to make use of Collaboration Candidates and related intellectual property (collectively, the “Scriptr Agreement”). ​ Pursuant to the Scriptr Agreement, Scriptr will use commercially reasonable efforts to carry out research activities set forth in accordance with the applicable DM1 Field and FA Field research plans, including certain pre-clinical proof of concept studies, to identify research Collaboration Candidates utilizing SPT (each, a “Research Program”). Following the completion of activities under a given Research Program, Scriptr will prepare and submit to the Company a comprehensive data package (each, a “Data Package”) that summarizes, on a Research Program-by-Research Program basis, any Collaboration Candidates researched under the Research Program, including any data and results. Upon receipt of a Data Package, the Company has, in its sole discretion, up to two-hundred seventy ( 270 ) calendar days to make effective the exclusive license agreement entered into by and between the Company and Scriptr, pursuant to which, among other things, Scriptr grants the Company exclusive rights and licenses with respect to the development, manufacture and commercialization of licensed candidates and products, subject to certain conditions and limitations (the “Scriptr License Agreement”), for a given Research Program (each licensed Research Program, a “Licensed Program”). The Scriptr License Agreement provides for customary development milestones on candidates developed under a Licensed Program and royalties on licensed products, if any. ​ In partial consideration of the rights granted by Scriptr to the Company under the Scriptr Agreement, the Company made a one-time, non-creditable and non-refundable payment to Scriptr during the first quarter of 2021. The Company reimburses Scriptr for costs incurred by or on behalf of Scriptr in connection with the conduct of each Research Program during the research term in accordance with the applicable Research Program budget and payment schedule. The Company incurred approximately ​ ​

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2022
Stock-Based Compensation
Stock-Based Compensation	Note 9. Stock-Based Compensation ​ As of June 30, 2022, the only equity compensation plans under which the Company may currently issue new awards are the Company’s 2013 Stock Incentive Plan (as amended to date, the “2013 Plan”) and 2017 Employee Stock Purchase Plan (as amended to date, the “2017 ESPP”), each as more fully described below. ​ Equity Incentive and Employee Stock Purchase Plans ​ 2013 Stock Incentive Plan ​ The 2013 Plan allows for the issuance of incentive stock options intended to qualify under the amended Section 422 of the Internal Revenue Code of 1986, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock units (“RSUs”), other stock-based awards and performance awards. ​ At the 2022 Annual Meeting of stockholders of the Company held on June 23, 2022 (the “Annual Meeting”), the Company’s stockholders approved an amendment (the “2022 Stock Plan Amendment”) to the Company’s 2013 Plan to increase the number of shares reserved for issuance under the 2013 Plan by 4,600,000 shares of the Company’s common stock. Accordingly, the total authorized shares of common stock under the 2013 Plan is increased to 10,253,057 shares of the Company’s common stock, plus such additional number of shares of common stock (up to 155,968 shares) as is equal to the number of shares of common stock subject to awards granted under the Company’s 2005 Stock Incentive Plan or 2008 Stock Incentive Plan (the “2008 Plan”), to the extent such awards expire, terminate or are otherwise surrendered, canceled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right. ​ As of June 30, 2022, options to purchase a total of 4,803,700 shares of common stock and 548,491 RSUs were outstanding and up to 4,648,994 shares of common stock remained available for grant under the 2013 Plan. ​ Other Awards and Inducement Grants ​ The Company has not made any awards pursuant to other equity incentive plans, including the 2008 Plan, since the Company’s stockholders approved the 2013 Plan. As of June 30, 2022, options to purchase a total of 145,968 shares of common stock were outstanding under the 2008 Plan. In addition, as of June 30, 2022, non-statutory stock options to purchase an aggregate of 325,000 shares of common stock were outstanding that were issued outside of the 2013 Plan to certain employees in 2015 and 2014 pursuant to the Nasdaq inducement grant exception as a material component of new hires’ employment compensation. ​ 2017 Employee Stock Purchase Plan ​ The 2017 ESPP is intended to qualify as an "employee stock purchase plan" as defined in Section 423 of the Internal Revenue Code, ​ At the Annual Meeting, the Company’s stockholders approved an amendment (the “2022 ESPP Amendment”) to the Company’s 2017 ESPP to increase the number of shares authorized for issuance under the 2017 ESPP by 600,000 shares of common stock. Accordingly, the total authorized shares of common stock under the 2017 ESPP is increased to 1,012,500 shares of common stock, subject to adjustment as described in the 2017 ESPP. As of June 30, 2022, 720,067 shares remained available for issuance under the 2017 ESPP. ​ For the six months ended June 30, 2022 and 2021, the Company issued 76,158 and 13,998 shares of common stock, respectively, under the 2017 ESPP and received proceeds of less than $0.1 million during each period, as a result of employee stock purchases. ​ ​ Note 9. Stock-Based Compensation (Continued) ​ Accounting for Stock-based Compensation ​ The Company recognizes non-cash compensation expense for stock-based awards under the Company’s equity incentive plans and employee stock purchases under the Company’s 2017 ESPP as follows: ● Stock Options : Compensation cost is recognized over an award’s requisite service period, or vesting period, using the straight-line attribution method, based on the grant date fair value determined using the Black-Scholes option-pricing model. ● RSUs : Compensation cost for time-based RSUs, which vest over time based only on continued service, is recognized on a straight-line basis over the requisite service period based on the fair value of the Company’s common stock on the date of grant. Compensation cost for awards that are subject to market considerations is recognized on a straight-line basis over the implied requisite service period, based on the grant date fair value estimated using a Monte Carlo simulation. Compensation cost for awards that are subject to performance conditions is recognized over the period of time commencing when the performance condition is deemed probable of achievement based on the fair value of the Company’s common stock on the date of grant. ● Employee Stock Purchases : Compensation cost is recognized over each plan period based on the fair value of the look-back provision, calculated using the Black-Scholes option-pricing model, considering the 15% discount on shares purchased. ​ Total stock-based compensation expense attributable to stock-based awards made to employees and directors and employee stock purchases included in operating expenses in the Company's condensed statements of operations for the three and six months ended June 30, 2022 and 2021 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ June 30, ​ June 30, (in thousands) ​ 2022 2021 ​ 2022 2021 Stock-based compensation: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Employee Stock Purchase Plan ​ $ 9 $ 3 ​ $ 15 $ 15 Equity Incentive Plan ​ ​ 52 ​ 50 ​ ​ 141 ​ 418 ​ ​ $ 61 $ 53 ​ $ 156 $ 433 General and administrative ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Employee Stock Purchase Plan ​ $ 1 $ 1 ​ $ 3 $ 3 Equity Incentive Plan ​ ​ 500 ​ 350 ​ ​ 948 ​ 1,079 ​ ​ $ 501 $ 351 ​ $ 951 $ 1,082 Total stock-based compensation expense ​ $ 562 $ 404 ​ $ 1,107 $ 1,515 ​ During the six months ended June 30, 2022 and 2021, the weighted average fair market value of stock options granted was $0.38 and $2.02, respectively. ​ The following weighted average assumptions apply to the options to purchase 660,700 and 833,500 shares of common stock granted to employees and directors during the six months ended June 30, 2022 and 2021, respectively: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 Average risk-free interest rate ​ 2.3% ​ ​ 0.4% ​ Expected dividend yield ​ ​ — ​ ​ — ​ Expected lives (years) ​ 4.0 ​ ​ 3.6 ​ Expected volatility ​ 102% ​ ​ 87% ​ Weighted average exercise price (per share) ​ $ 0.53 ​ $ 3.66 ​ ​ All options granted during the six months ended June 30, 2022 and 2021 were granted at exercise prices equal to the fair market value of the Company’s common stock on the dates of grant . Note 9. Stock-Based Compensation (Continued) ​ Stock Option Activity ​ The following table summarizes stock option activity for the six months ended June 30, 2022: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ($ in thousands, except per share data) ​ Stock Options ​ Weighted-Average Exercise Price ​ Weighted-Average Remaining Contractual Life (in years) ​ Aggregate Intrinsic Value Outstanding at December 31, 2021 5,202,006 ​ $ 8.06 5.9 ​ $ 2,949 ​ Granted 660,700 ​ ​ 0.53 ​ ​ ​ ​ ​ ​ Exercised — ​ ​ — ​ ​ ​ ​ ​ ​ Forfeited — ​ ​ — ​ ​ ​ ​ ​ ​ Expired (588,038) ​ ​ 2.87 ​ ​ ​ ​ ​ ​ Outstanding at June 30, 2022 (1) 5,274,668 ​ $ 7.70 ​ 6.6 ​ $ — ​ Exercisable at June 30, 2022 3,818,724 ​ $ 10.16 ​ 5.6 ​ $ — ​ (1) Includes both vested stock options as well as unvested stock options for which the requisite service period has not been rendered but that are expected to vest based on achievement of a service condition. ​ As of June 30, 2022, there was $1.0 million of unrecognized compensation cost related to unvested options, which the Company expects to recognize over a weighted average period of 2.3 years. During the three months ended March 31, 2021, the Company accelerated the vesting of 1,535,578 options, which were previously granted from 2019 through 2021. The modification resulted in an incremental stock-based compensation charge that was not significant. In January 2022, for members of the Company’s Leadership team, the Compensation Committee of the Board of Directors implemented a post-exercise holding period prohibiting the sale of shares associated with the 2021 Acceleration on any schedule more favorable than the original vesting schedule (i.e., 6.25% of the total option grant every quarter and 25% of the total RSU grant every year). This post-exercise holding period has no financial statement impact. ​ Restricted Stock Activity ​ The following table summarizes restricted stock activity for the six months ended June 30, 2022: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Time-based Awards ​ Market/Performance-based Awards ($ in thousands, except per share data) ​ Number of Shares ​ Weighted-Average Grant Date Fair Value ​ Number of Shares ​ Weighted-Average Grant Date Fair Value Nonvested shares at December 31, 2021 68,675 ​ $ 2.30 ​ 507,028 ​ $ 1.54 Granted — ​ — ​ — ​ — Cancelled — ​ — ​ — ​ — Vested (27,212) ​ 2.43 ​ — ​ — Nonvested shares at June 30, 2022 41,463 ​ $ 2.21 ​ 507,028 ​ $ 1.54 ​ Time-based Restricted Stock Units ​ During the three months ended March 31, 2021, the Company accelerated the vesting of 137,872 unvested time-based RSUs which were previously granted in 2019 and 2020. The modification resulted in an incremental stock-based compensation charge that was not significant. ​ During the six months ended June 30, 2022, the Company recognized $0.1 million of compensation expense related to these awards. As of June 30, 2022, there was $0.1 million of unrecognized compensation expense related to the Company’s time-based RSUs, which is expected to be recognized over a weighted-average period of 1.2 years. ​ Note 9. Stock-Based Compensation (Continued) ​ Market/Performance-based Restricted Stock Units ​ In July 2020, the Company granted RSUs to certain employees, including executive officers, under the 2013 Plan, with vesting that may occur upon a combination of specific performance and/or market conditions. Accordingly, the Company views these RSUs as two separate awards: (i) an award that vests if the market condition is achieved, and (ii) an award that vests whether or not the market condition is achieved, so long as the performance condition is achieved. The Company is currently recognizing compensation expense for these awards over the estimated requisite service period of 2.36 years based on the estimated fair value when considering the market condition of the award, which was determined using a Monte Carlo simulation. ​ During the six months ended June 30, 2022, the Company recognized $0.1 million of compensation expense related to these awards. As of June 30, 2022, the remaining unrecognized compensation cost for the market-based component of these awards, which is expected to be recognized over a weighted-average period of 0.4 years, is $0.1 million. In addition, should the performance condition be achieved, the Company would recognize an additional $0.3 million of compensation expense.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2022
Related Party Transactions
Related Party Transactions	Note 10. Related Party Transactions ​ Baker Brothers ​ Julian C. Baker, a member of the Company’s Board of Directors until his resignation in September 2018, is a principal of Baker Bros. Advisors, LP. Additionally, Kelvin M. Neu, a member of Company’s Board of Directors until his resignation in June 2019, is an employee of Baker Bros. Advisors, LP. At December 31, 2020, Baker Bros. Advisors, LP and certain of its affiliated funds (collectively, “Baker Brothers”) held sole voting power with respect to an aggregate of 4,608,786 shares of the Company’s common stock, representing approximately 12% of the Company's then outstanding common stock. ​ During the six months ended June 30, 2021, Baker Brothers exercised warrants to purchase 2,708,812 shares of the Company’s common stock at an exercise price of $0.08 per share for a total exercise price of approximately $0.2 million. Additionally, during the six ​ At June 30, 2022, Baker Brothers held sole voting power with respect to an aggregate of 2,047,180 shares of the Company’s common stock, representing approximately 4% of the Company's outstanding common stock. ​ Pillar Investment Entities ​ Youssef El Zein, a member of the Company’s Board of Directors until his resignation in October 2017, is a director and controlling stockholder of Pillar Invest Corporation (“Pillar Invest”), which is the general partner of Pillar Pharmaceuticals I, L.P., Pillar Pharmaceuticals II, L.P., Pillar Pharmaceuticals III, L.P., Pillar Pharmaceuticals IV, L.P., Pillar Pharmaceuticals V, L.P., Pillar 6, Pillar 7, and Pillar Partners (collectively, the “Pillar Investment Entities”). As of June 30, 2022, the Pillar Investment Entities owned approximately 16% of the Company's common stock and beneficially owned approximately 19.99% of the Company's common stock. ​ As of June 30, 2022, the Pillar Investment Entities held (i) prefunded warrants to purchase up to 1,533,159 shares of the Company’s common stock at an exercise price of $0.01 per share, (ii) warrants to purchase up to 3,039,514 shares of the Company’s common stock at an exercise price of $2.28 per share, (iii) warrants to purchase up to 2,764,227 shares of the Company’s common stock at an exercise price of $2.58 per share, and (iv) warrants to purchase up to 1,373,626 shares of the Company’s common stock at an exercise price of $2.71 per share. ​ During the , certain of the Pillar Investment Entities exercised warrants to purchase 3,158,386 shares of the Company’s common stock at an exercise price of $0.01 per share for a total exercise price of less than $0.1 million. 19,052 shares were used to fund the exercise costs. ​ Note 10. Related Party Transactions (Continued) ​ Board Fees Paid in Stock ​ Pursuant to the Company’s director compensation program, in lieu of director board and committee fees of $0.1 million during each of the six months ended June 30, 2022 and 2021, the Company issued 91,241 and 47,400 shares of common stock, respectively, to certain of its directors. Director board and committee fees are paid in arrears and the number of shares issued was calculated based on the market closing price of the Company’s common stock on the issuance date.

Net Income (Loss) per Common Sh

Net Income (Loss) per Common Share	6 Months Ended
	Jun. 30, 2022
Net Income (Loss) per Common Share
Net Income (Loss) per Common Share	Note 11. Net Income (Loss) per Common Share ​ During periods the Company realizes net income, it uses the two-class method to compute net income per common share and has securities outstanding (redeemable convertible preferred stock) that entitle the holder to participate in dividends and earnings of the Company. In addition, the Company analyzes the potential dilutive effect of outstanding redeemable convertible preferred stock under the "if-converted" method when calculating diluted earnings per share and reports the more dilutive of the approaches (two class or "if-converted"). The two-class method is not applicable during periods with a net loss, as the holders of the redeemable convertible preferred stock have no obligation to fund losses. ​ The Company also analyzes the potential dilutive effect of stock options, restricted stock units, warrants and shares underlying future tranche rights under the treasury stock method (as applicable), during periods of income, or during periods in which income is recognized related to changes in fair value of its liability-classified securities. ​ For the six months ended June 30, 2021, the Company used the two-class method to compute net income per common share. Under this method, net income is reduced by the amount of any dividends earned and the accretion of redeemable convertible preferred stock to its redemption value, if any, during the period. The remaining earnings (undistributed earnings) are allocated to common stock and each series of redeemable convertible preferred stock to the extent that each preferred security may share in earnings as if all the earnings for the period had been distributed. The total earnings allocated to common stock is then divided by the number of outstanding shares to which the earnings are allocated to determine the earnings per share. ​ However, during periods the Company realizes net loss, basic and diluted net loss per common share applicable to common stockholders is calculated by dividing net loss applicable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration of common stock equivalents. The Company’s potentially dilutive shares, which include outstanding stock option awards, common stock warrants and convertible preferred stock, are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. ​ For the three and six months ended June 30, 2022, diluted net loss per common share applicable to common stockholders was the same as basic net loss per common share applicable to common stockholders as the effects of the Company’s potential common stock equivalents were antidilutive. ​ ​ Note 11. Net Income (Loss) per Common Share (Continued) ​ Details in the computation of basic and diluted net income (loss) per common share were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ June 30, ​ June 30, ($ in thousands except per share data) ​ ​ 2022 ​ ​ 2021 ​ ​ 2022 ​ ​ 2021 Net income (loss) per share — Basic: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ (5,307) ​ $ (7,563) ​ $ (9,485) ​ $ 108,175 Less: Undistributed earnings to preferred stockholders ​ ​ — ​ ​ — ​ ​ ​ ​ ​ (2,725) Net income (loss) applicable to common stockholders - basic ​ $ (5,307) ​ $ (7,563) ​ $ (9,485) ​ $ 105,450 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator for basic net income (loss) applicable to common stockholders ​ $ (5,307) ​ $ (7,563) ​ $ (9,485) ​ $ 105,450 Denominator for basic net income (loss) applicable to common stockholders ​ ​ 52,972 ​ ​ 49,909 ​ ​ 52,933 ​ ​ 45,575 Net income (loss) applicable to common stockholders - basic ​ $ (0.10) ​ $ (0.15) ​ $ (0.18) ​ $ 2.31 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) per share — Diluted: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ (5,307) ​ $ (7,563) ​ $ (9,485) ​ $ 108,175 Less: Warrant revaluation gain applicable to dilutive liability-classified warrants ​ ​ — ​ ​ — ​ ​ — ​ ​ (6,983) Less: Future tranche right revaluation gain applicable to dilutive liability-classified future tranche rights ​ ​ — ​ ​ — ​ ​ — ​ ​ (118,803) Numerator for diluted net income (loss) applicable to common stockholders ​ $ (5,307) ​ $ (7,563) ​ $ (9,485) ​ $ (17,611) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator for basic net income (loss) applicable to common stockholders ​ ​ 52,972 ​ ​ 49,909 ​ ​ 52,933 ​ ​ 45,575 Plus: Incremental shares underlying “in the money” liability-classified warrants outstanding ​ ​ — ​ ​ — ​ ​ — ​ ​ 496 Plus: Incremental shares underlying “in the money” liability-classified future tranche rights outstanding ​ ​ — ​ ​ — ​ ​ — ​ ​ 8,866 Denominator for diluted net income (loss) applicable to common stockholders ​ ​ 52,972 ​ ​ 49,909 ​ ​ 52,933 ​ ​ 54,937 Net income (loss) applicable to common stockholders - diluted ​ $ (0.10) ​ $ (0.15) ​ $ (0.18) ​ $ (0.32) ​ ​ ​ Note 11. Net Income (Loss) per Common Share (Continued) ​ Total antidilutive securities excluded from the calculation of diluted net loss per share for the three and six months ended June 30, 2022 and 2021 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ June 30, ​ June 30, (in thousands) ​ ​ 2022 ​ ​ 2021 ​ ​ 2022 ​ ​ 2021 Stock options ​ ​ 5,275 ​ ​ 4,888 ​ ​ 5,275 ​ ​ 4,888 Restricted stock units ​ ​ 548 ​ ​ 594 ​ ​ 548 ​ ​ 594 Common stock warrants ​ ​ 8,732 ​ ​ 8,732 ​ ​ 8,732 ​ ​ 8,732 Total ​ ​ 14,555 ​ ​ 14,214 ​ ​ 14,555 ​ ​ 14,214 ​

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2022
Subsequent Events
Subsequent Events	Note 12. Subsequent Events ​ The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. ​ ​

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2022
Summary of Significant Accounting Policies
Basis of Presentation	Basis of Presentation ​ The accompanying unaudited financial statements included herein have been prepared by the Company in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to the rules and regulations of the SEC. Accordingly, 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. In the opinion of management, all adjustments, consisting of normal recurring adjustments, and disclosures considered necessary for a fair presentation of interim period results have been included. Interim results for the three and six months ended June 30, 2022 are not necessarily indicative of results that may be expected for the year ending December 31, 2022. For further information, refer to the financial statements and footnotes thereto included in the Company’s 2021 Form 10-K. ​
Cash and Cash Equivalents	Cash and Cash Equivalents ​ The Company considers all highly liquid investments with maturities of 90 days or less when purchased to be “cash equivalents.” Cash and cash equivalents at June 30, 2022 and December 31, 2021 consisted of cash and money market funds.
Financial Instruments	Financial Instruments ​ The fair value of the Company’s financial instruments is determined and disclosed in accordance with the three-tier fair value hierarchy specified in Note 3. The Company is required to disclose the estimated fair values of its financial instruments. As of June 30, 2022 and December 31, 2021, the Company’s financial instruments consisted of cash and cash equivalents. The estimated fair values of these financial instruments approximate their carrying values. As of June 30, 2022, the Company did not have any derivatives, hedging instruments or other similar financial instruments.
Concentration of Credit Risk	Concentration of Credit Risk ​ Financial instruments that subject the Company to credit risk primarily consist of cash and cash equivalents. The Company’s credit risk is managed by investing in highly rated money market instruments, U.S. treasury bills, corporate bonds, commercial paper and/or other debt securities. Due to these factors, no significant additional credit risk is believed by management to be inherent in the Company’s assets. As of June 30, 2022, all the Company’s cash and cash equivalents were held at two financial institutions.
Operating Lease Right-of-use Asset and Lease Liability	Operating Lease Right-of-use Assets and Lease Liability ​ The Company accounts for leases under ASC 842, Leases. Operating leases are included in “Operating lease right-of-use assets” within the Company’s balance sheets and represent the Company’s right to use an underlying asset for the lease term. The Company’s related obligation to make lease payments are included in “Operating lease liability” and “Operating lease liability, net of current portion” within the Company’s balance sheets. Operating lease right-of-use (“ROU”) assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rates, which are the rates incurred to borrow on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The ROU assets are tested for impairment according to ASC 360, Property, Plant, and Equipmen ​ As of June 30, 2022 and December 31, 2021, the Company’s operating lease ROU assets and corresponding short-term and long-term lease liabilities primarily relate to its existing Exton, PA facility operating lease which expires on May 31, 2025.
Warrant Liability	Warrant Liability ​ The Company accounts for stock warrants as either equity instruments, liabilities or derivative liabilities in accordance with ASC 480, Distinguishing Liabilities from Equity Derivatives and Hedging , depending on the specific terms of the warrant agreement. Freestanding warrants for shares that are potentially redeemable, whereby the Company may be required to transfer assets (e.g. cash or other assets) outside of its control, are classified as liabilities. Liability-classified warrants are recorded at their estimated fair values at each reporting period until they are exercised, terminated, reclassified or otherwise settled. Changes in the estimated fair value of liability-classified warrants are recorded in Warrant Revaluation Gain (Loss) in the Company’s condensed statements of operations. Equity classified warrants are recorded within additional paid-in capital at the time of issuance and not subject to remeasurement. During the three months ended March 31, 2021, all of the Company’s liability-classified warrants terminated and, accordingly, the liability balance was derecognized. ​
Future Tranche Right Liability	Future Tranche Right Liability ​ On December 23, 2019, the Company entered into a Securities Purchase Agreement (the “December 2019 Securities Purchase Agreement”) with institutional investors affiliated with Baker Brothers, an existing stockholder (see Note 10). As more fully described in Note 6, the December 2019 Securities Purchase Agreement contained call options on redeemable preferred shares with warrants (conditionally exercisable for shares that are puttable). The Company determined that these call options represented freestanding financial instruments and accounted for the options as liabilities (“Future Tranche Right Liability”) under ASC 480, which requires the measurement and recognition of the fair value of the liability at the time of issuance and at each reporting period. Any change in fair value was recognized in Future Tranche Right Liability Revaluation Gain (Loss) in the Company’s condensed statements of operations. During the three months ended March 31, 2021, the liability-classified call options provided for under the December 2019 Securities Purchase Agreement terminated and, accordingly, the liability balance was derecognized. ​
Preferred Stock	Preferred Stock ​ The Company applies ASC 480 when determining the classification and measurement of its preferred stock. Preferred shares subject to mandatory redemption are classified as liability instruments and are measured at fair value. Conditionally redeemable preferred shares (including preferred shares that feature redemption rights that are either within the control of the holder or subject to redemption upon the occurrence of uncertain events not solely within the Company’s control) are classified as temporary equity. At all other times, preferred shares are classified as stockholders’ equity. ​ Accretion of redeemable convertible preferred stock includes the accretion of the Company's Series B redeemable convertible preferred stock to its stated value. The carrying value of the Series B redeemable convertible preferred stock is accreted to redemption value using the effective interest method, from the date of issuance to the earliest date the holders can demand redemption or until the redeemable convertible preferred stock cease to be outstanding.
Income Taxes	Income Taxes ​ In accordance with ASC 270, Interim Reporting Income Taxes
New Accounting Pronouncements	New Accounting Pronouncements ​ From time to time, new accounting pronouncements are issued by the FASB and rules are issued by the SEC that the Company has or will adopt as of a specified date. Unless otherwise noted, management does not believe that any other recently issued accounting pronouncements issued by the FASB or guidance issued by the SEC had, or is expected to have, a material impact on the Company’s present or future financial statements. ​ Recently Adopted Accounting Pronouncements ​ In August 2020, the FASB issued Accounting Standard Update (“ASU”) No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”), which simplifies the guidance on an issuer’s accounting for convertible instruments and contracts in its own equity. The Company adopted ASU 2020-06 in the first quarter of 2021. The adoption of ASU 2020-06 did not have a material effect on the Company’s financial statements.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2022
Fair Value Measurements
Schedule of assets and liabilities measured and recorded in financial statements at fair value on a recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2022 (In thousands) ​ Total ​ Level 1 ​ Level 2 ​ Level 3 Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash ​ $ 250 ​ $ 250 ​ $ — ​ $ — ​ Cash equivalents – money market funds ​ ​ 24,230 ​ ​ 24,230 ​ ​ — ​ ​ — ​ Total assets ​ $ 24,480 ​ $ 24,480 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ (In thousands) ​ Total ​ Level 1 ​ Level 2 ​ Level 3 ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash ​ $ 250 ​ $ 250 ​ $ — ​ $ — ​ Cash equivalents – money market funds ​ ​ 32,295 ​ ​ 32,295 ​ ​ — ​ ​ — ​ Total assets ​ $ 32,545 ​ $ 32,545 ​ $ — ​ $ — ​
Schedule of reconciliation measured at fair value on a recurring basis using unobservable inputs	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Future ​ ​ Warrant ​ Tranche Right (In thousands) ​ Liability ​ Liability Balance, December 31, 2020 $ 6,983 ​ $ 118,803 Change in the fair value of liability (1) (6,983) ​ (118,803) Balance, June 30, 2021 $ — ​ $ — (1) During the six months ended June 30, 2021, the Company’s liability-classified warrants and future tranche rights terminated, and accordingly, the liabilities were derecognized.

Property and Equipment (Tables)

Property and Equipment (Tables)	6 Months Ended
	Jun. 30, 2022
Property and Equipment
Schedule of net property and equipment at cost	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ (In thousands) 2022 2021 Leasehold improvements ​ $ 107 ​ $ 107 ​ Equipment and other ​ 712 ​ 712 ​ Total property and equipment, at cost ​ $ 819 ​ $ 819 ​ Less: Accumulated depreciation and amortization ​ 805 ​ 797 ​ Property and equipment, net ​ $ 14 ​ $ 22 ​ ​ ​

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2022
Accrued Expenses
Schedule of accrued expenses	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, (In thousands) ​ 2022 2021 Payroll and related costs ​ $ 706 ​ $ 477 ​ Clinical and nonclinical trial expenses ​ 2,984 ​ 2,909 ​ Professional and consulting fees ​ 587 ​ 591 ​ Other ​ 93 ​ 111 ​ Total accrued expenses ​ $ 4,370 ​ $ 4,088 ​

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2022
Stockholders' Equity
Schedule of warrants outstanding and exercisable for purchase of common stock	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of Shares ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ Weighted-Average ​ ​ ​ Description ​ 2022 ​ 2021 ​ Exercise Price ​ Expiration Date ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity-classified Warrants ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ May 2013 warrants 15,437 ​ 15,437 ​ ​ $ 0.08 ​ None ​ September 2013 warrants 4,096 ​ 4,096 ​ ​ $ 0.08 ​ None ​ February 2014 warrants 2,171 ​ 2,171 ​ ​ $ 0.08 ​ None ​ April 2020 Private Placement first closing warrants ​ 3,039,514 ​ 3,039,514 ​ ​ $ 2.28 ​ Apr 2023 ​ April 2020 Private Placement second closing warrants ​ 1,373,626 ​ 1,373,626 ​ ​ $ 2.71 ​ Dec 2023 ​ April 2020 Private Placement second closing warrants ​ 1,143,428 ​ 1,143,428 ​ ​ $ 0.01 ​ None ​ July 2020 Private Placement first closing warrants ​ 389,731 ​ 389,731 ​ ​ $ 0.01 ​ None ​ July 2020 Private Placement first closing warrants ​ 2,764,227 ​ 2,764,227 ​ ​ $ 2.58 ​ Jul 2023 ​ ​ ​ 8,732,230 ​ 8,732,230 ​ ​ ​ ​ ​ ​ Total outstanding 8,732,230 ​ 8,732,230 ​ ​ ​ ​ ​ ​

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2022
Stock-Based Compensation
Schedule of stock-based compensation expense attributable to share-based payments made to employees and directors and included in operating expenses	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ June 30, ​ June 30, (in thousands) ​ 2022 2021 ​ 2022 2021 Stock-based compensation: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Employee Stock Purchase Plan ​ $ 9 $ 3 ​ $ 15 $ 15 Equity Incentive Plan ​ ​ 52 ​ 50 ​ ​ 141 ​ 418 ​ ​ $ 61 $ 53 ​ $ 156 $ 433 General and administrative ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Employee Stock Purchase Plan ​ $ 1 $ 1 ​ $ 3 $ 3 Equity Incentive Plan ​ ​ 500 ​ 350 ​ ​ 948 ​ 1,079 ​ ​ $ 501 $ 351 ​ $ 951 $ 1,082 Total stock-based compensation expense ​ $ 562 $ 404 ​ $ 1,107 $ 1,515
Schedule of weighted average assumptions applied to options	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 Average risk-free interest rate ​ 2.3% ​ ​ 0.4% ​ Expected dividend yield ​ ​ — ​ ​ — ​ Expected lives (years) ​ 4.0 ​ ​ 3.6 ​ Expected volatility ​ 102% ​ ​ 87% ​ Weighted average exercise price (per share) ​ $ 0.53 ​ $ 3.66 ​
Schedule of information related to outstanding and exercisable options	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ($ in thousands, except per share data) ​ Stock Options ​ Weighted-Average Exercise Price ​ Weighted-Average Remaining Contractual Life (in years) ​ Aggregate Intrinsic Value Outstanding at December 31, 2021 5,202,006 ​ $ 8.06 5.9 ​ $ 2,949 ​ Granted 660,700 ​ ​ 0.53 ​ ​ ​ ​ ​ ​ Exercised — ​ ​ — ​ ​ ​ ​ ​ ​ Forfeited — ​ ​ — ​ ​ ​ ​ ​ ​ Expired (588,038) ​ ​ 2.87 ​ ​ ​ ​ ​ ​ Outstanding at June 30, 2022 (1) 5,274,668 ​ $ 7.70 ​ 6.6 ​ $ — ​ Exercisable at June 30, 2022 3,818,724 ​ $ 10.16 ​ 5.6 ​ $ — ​ (1) Includes both vested stock options as well as unvested stock options for which the requisite service period has not been rendered but that are expected to vest based on achievement of a service condition.
Schedule of information related to restricted stock activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Time-based Awards ​ Market/Performance-based Awards ($ in thousands, except per share data) ​ Number of Shares ​ Weighted-Average Grant Date Fair Value ​ Number of Shares ​ Weighted-Average Grant Date Fair Value Nonvested shares at December 31, 2021 68,675 ​ $ 2.30 ​ 507,028 ​ $ 1.54 Granted — ​ — ​ — ​ — Cancelled — ​ — ​ — ​ — Vested (27,212) ​ 2.43 ​ — ​ — Nonvested shares at June 30, 2022 41,463 ​ $ 2.21 ​ 507,028 ​ $ 1.54

Net Income (Loss) per Common _2

Net Income (Loss) per Common Share (Tables)	6 Months Ended
	Jun. 30, 2022
Net Income (Loss) per Common Share
Computation of basic and diluted net income (loss) per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ June 30, ​ June 30, ($ in thousands except per share data) ​ ​ 2022 ​ ​ 2021 ​ ​ 2022 ​ ​ 2021 Net income (loss) per share — Basic: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ (5,307) ​ $ (7,563) ​ $ (9,485) ​ $ 108,175 Less: Undistributed earnings to preferred stockholders ​ ​ — ​ ​ — ​ ​ ​ ​ ​ (2,725) Net income (loss) applicable to common stockholders - basic ​ $ (5,307) ​ $ (7,563) ​ $ (9,485) ​ $ 105,450 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator for basic net income (loss) applicable to common stockholders ​ $ (5,307) ​ $ (7,563) ​ $ (9,485) ​ $ 105,450 Denominator for basic net income (loss) applicable to common stockholders ​ ​ 52,972 ​ ​ 49,909 ​ ​ 52,933 ​ ​ 45,575 Net income (loss) applicable to common stockholders - basic ​ $ (0.10) ​ $ (0.15) ​ $ (0.18) ​ $ 2.31 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) per share — Diluted: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ (5,307) ​ $ (7,563) ​ $ (9,485) ​ $ 108,175 Less: Warrant revaluation gain applicable to dilutive liability-classified warrants ​ ​ — ​ ​ — ​ ​ — ​ ​ (6,983) Less: Future tranche right revaluation gain applicable to dilutive liability-classified future tranche rights ​ ​ — ​ ​ — ​ ​ — ​ ​ (118,803) Numerator for diluted net income (loss) applicable to common stockholders ​ $ (5,307) ​ $ (7,563) ​ $ (9,485) ​ $ (17,611) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator for basic net income (loss) applicable to common stockholders ​ ​ 52,972 ​ ​ 49,909 ​ ​ 52,933 ​ ​ 45,575 Plus: Incremental shares underlying “in the money” liability-classified warrants outstanding ​ ​ — ​ ​ — ​ ​ — ​ ​ 496 Plus: Incremental shares underlying “in the money” liability-classified future tranche rights outstanding ​ ​ — ​ ​ — ​ ​ — ​ ​ 8,866 Denominator for diluted net income (loss) applicable to common stockholders ​ ​ 52,972 ​ ​ 49,909 ​ ​ 52,933 ​ ​ 54,937 Net income (loss) applicable to common stockholders - diluted ​ $ (0.10) ​ $ (0.15) ​ $ (0.18) ​ $ (0.32)
Schedule of potentially dilutive securities excluded from diluted net income (loss) per common share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ June 30, ​ June 30, (in thousands) ​ ​ 2022 ​ ​ 2021 ​ ​ 2022 ​ ​ 2021 Stock options ​ ​ 5,275 ​ ​ 4,888 ​ ​ 5,275 ​ ​ 4,888 Restricted stock units ​ ​ 548 ​ ​ 594 ​ ​ 548 ​ ​ 594 Common stock warrants ​ ​ 8,732 ​ ​ 8,732 ​ ​ 8,732 ​ ​ 8,732 Total ​ ​ 14,555 ​ ​ 14,214 ​ ​ 14,555 ​ ​ 14,214

Business and Organization (Deta

Business and Organization (Details) $ in Thousands		3 Months Ended	6 Months Ended
	May 26, 2022	Jun. 30, 2021 USD ($) employee	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Business and Organization
Percentage of positions eliminated		50%
Restructuring and Related Cost, Number of Positions Eliminated | employee		16
Restructuring costs		$ 1,192	$ 1,192
Accumulated deficit				$ 744,946	$ 735,461
Cash, cash equivalents and investments				$ 24,500
Additional compliance period	180 days
Number of consecutive business days considered for minimum closing bid price	10 days

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) Institution	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Summary of Significant Accounting Policies
Number of financial institutions | Institution			2
Uncertain tax positions	$ 0		$ 0		$ 0
Tax expense (benefit)	$ 0	$ 0	$ 0	$ 0

Fair Value Measurements - Trans

Fair Value Measurements - Transfers Between Levels (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Fair Value Measurements
Fair value of assets transfers from level 1 to level 2	$ 0
Fair value of assets transfers from level 2 to level 1	0
Fair value of liabilities transfers from level 1 to level 2	0
Fair value of liabilities transfers from level 2 to level 1	0
Fair value of assets transfers into level 3	0
Fair value of assets transfers out of level 3	0
Fair value of liabilities transfers into level 3	0
Fair value of liabilities transfers out of level 3	$ 0

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total Assets	$ 24,480	$ 32,545
Cash
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Cash and Money market funds	250	250
Money Market Funds [Member]
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Cash and Money market funds	24,230	32,295
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member]
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total Assets	24,480	32,545
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Cash
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Cash and Money market funds	250	250
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Money Market Funds [Member]
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Cash and Money market funds	$ 24,230	$ 32,295

Fair Value Measurements - Ass_2

Fair Value Measurements - Assets and Liabilities at Fair Value Changes in Level 3 Liabilities (Details) - Fair Value, Measurements, Recurring [Member] $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)
Warrant liability
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Beginning balance	$ 6,983
Change in the fair value of liability (1)	(6,983)
Future tranche right liability
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Beginning balance	118,803
Change in the fair value of liability (1)	$ (118,803)

Property and Equipment - Net Pr

Property and Equipment - Net Property and Equipment at Cost (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Property, Plant and Equipment
Total property and equipment, at cost	$ 819	$ 819
Less: Accumulated depreciation and amortization	805	797
Property and equipment, net	14	22
Leasehold improvements
Property, Plant and Equipment
Total property and equipment, at cost	107	107
Equipment and other
Property, Plant and Equipment
Total property and equipment, at cost	$ 712	$ 712

Property and Equipment - Deprec

Property and Equipment - Depreciation and Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Property, Plant and Equipment
Non-cash property additions	$ 0	$ 0	$ 0	$ 0
Maximum
Property, Plant and Equipment
Depreciation and amortization expense on property and equipment	$ 100	$ 100	$ 100	$ 100

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Accrued Expenses
Payroll and related costs	$ 706	$ 477
Clinical and nonclinical trial expenses	2,984	2,909
Professional and consulting fees	587	591
Other	93	111
Total accrued expenses	$ 4,370	$ 4,088

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended	3 Months Ended		6 Months Ended
	Dec. 23, 2019	Dec. 31, 2019	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021	Jun. 30, 2022	Dec. 31, 2021
Temporary Equity
Aggregate gross proceeds	$ 3.9
Gross proceeds		$ 6.2
Common Stock, Shares Authorized		140,000,000				140,000,000	140,000,000
Series B1 Redeemable Convertible Preferred Stock
Temporary Equity
Sale of redeemable convertible preferred stock	23,684
Conversion of preferred stock to common, shares			10,000	14,000	23,684
Series B1 Redeemable Convertible Preferred Stock | Common stock warrants
Temporary Equity
Warrant to purchase stock	2,368,400
Warrant exercised price (per share)	$ 1.52
Series B1 Redeemable Convertible Preferred Stock | Preferred Stock Warrant
Temporary Equity
Warrant to purchase stock	23,684
Warrant exercised price (per share)	$ 152
Series B2 Redeemable Convertible Preferred Stock
Temporary Equity
Aggregate gross proceeds	$ 15
Preferred Shares	98,685
Series B2 Redeemable Convertible Preferred Stock | Common stock warrants
Temporary Equity
Warrant to purchase stock	9,868,500
Warrant exercised price (per share)	$ 1.52
Series B2 Redeemable Convertible Preferred Stock | Preferred Stock Warrant
Temporary Equity
Warrant to purchase stock	98,685
Warrant exercised price (per share)	$ 152
Series B3 Redeemable Convertible Preferred Stock
Temporary Equity
Aggregate gross proceeds	$ 15
Preferred Shares	82,418
Series B3 Redeemable Convertible Preferred Stock | Common stock warrants
Temporary Equity
Warrant to purchase stock	6,593,440
Warrant exercised price (per share)	$ 1.82
Series B3 Redeemable Convertible Preferred Stock | Preferred Stock Warrant
Temporary Equity
Warrant to purchase stock	65,934
Warrant exercised price (per share)	$ 182
Series B4 Redeemable Convertible Preferred Stock
Temporary Equity
Aggregate gross proceeds	$ 15
Preferred Shares	82,418
Expiration period	21 months
Series B4 Redeemable Convertible Preferred Stock | Common stock warrants
Temporary Equity
Warrant to purchase stock	6,593,440
Warrant exercised price (per share)	$ 1.82
Series B4 Redeemable Convertible Preferred Stock | Preferred Stock Warrant
Temporary Equity
Warrant to purchase stock	65,934
Warrant exercised price (per share)	$ 182

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock (Details) - USD ($)				1 Months Ended	6 Months Ended		27 Months Ended
	Jul. 13, 2020	Apr. 07, 2020	Mar. 04, 2019	Nov. 30, 2018	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022
April 2020 Private Placement Second Closing
Class of Stock
Ownership percentage		19.99%
"At-The-Market" Equity Program
Class of Stock
Maximum value of shares that are permitted to be sold, subject to certain limitations					$ 19,500,000
Stock issued (in shares)					0	4,470,593
Net proceeds from offering of common stock				$ 50,000,000		$ 14,600,000
Percentage of fixed commission expense of gross proceeds of shares sold in ATM agreement				3%
Lincoln Park Capital Fund, LLC ("Investor")
Class of Stock
Value of shares which may be sold			$ 35,000,000
Duration over which common stock purchase agreement may be sold			36 months
Stock issued (in shares)			269,749			800,000
Stock issued (per share)			$ 2.84
Net proceeds from offering of common stock						$ 4.2
April 2020 Private Placement
Class of Stock
Stock issued (in shares)		3,039,514
Shares of common stock that may be purchased upon exercise of warrants		3,039,514
Warrant exercised price (per share)		$ 2.28
Gross proceeds from sale of common stock and warrants excluding the proceeds from exercise of the warrants, if any		$ 5,000,000
Combined purchase price (per share)		$ 1.645
Stock price underlying warrants (per share)		$ 0.125
April 2020 Private Placement Second Closing
Class of Stock
Stock issued (in shares)		2,747,252
Shares of common stock that may be purchased upon exercise of warrants		1,373,626
Warrant exercised price (per share)		$ 2.71
Gross proceeds from sale of common stock and warrants excluding the proceeds from exercise of the warrants, if any		$ 5,000,000
Stock price (in dollars per share)		$ 0.01
April 2020 Private Placement and April 2020 Private Placement Second Closing in Aggregate
Class of Stock
Net proceeds from offering of common stock							$ 9,800,000
July 2020 Private Placement Second Closing
Class of Stock
Gross proceeds from sale of common stock and warrants excluding the proceeds from exercise of the warrants, if any	$ 5,100,000
July 2020 Private Placement Second Closing | Pre-funded Warrants
Class of Stock
Stock issued (in shares)	784,615
Stock price (in dollars per share)	$ 0.01
July 2020 Private Placement Second Closing | Warrants
Class of Stock
Shares of common stock that may be purchased upon exercise of warrants	274,615
Warrant exercised price (per share)	$ 9.75

Stockholders' Equity - Common_2

Stockholders' Equity - Common Stock Warrants (Details) - $ / shares	Jun. 30, 2022	Dec. 31, 2021
Class of Warrant or Right
Number of Shares	8,732,230	8,732,230
Equity Classified Warrants
Class of Warrant or Right
Number of Shares	8,732,230	8,732,230
May 2013 Warrants
Class of Warrant or Right
Number of Shares	15,437	15,437
Weighted-Average Exercise Price	$ 0.08
September 2013 Warrants
Class of Warrant or Right
Number of Shares	4,096	4,096
Weighted-Average Exercise Price	$ 0.08
February 2014 Warrants
Class of Warrant or Right
Number of Shares	2,171	2,171
Weighted-Average Exercise Price	$ 0.08
April 2020 Private Placement first closing warrants
Class of Warrant or Right
Number of Shares	3,039,514	3,039,514
Weighted-Average Exercise Price	$ 2.28
April 2020 Private Placement second closing warrants
Class of Warrant or Right
Number of Shares	1,373,626	1,373,626
Weighted-Average Exercise Price	$ 2.71
April 2020 Private Placement second closing warrants
Class of Warrant or Right
Number of Shares	1,143,428	1,143,428
Weighted-Average Exercise Price	$ 0.01
July 2020 Private Placement first closing warrants
Class of Warrant or Right
Number of Shares	389,731	389,731
Weighted-Average Exercise Price	$ 0.01
July 2020 Private Placement first closing warrants
Class of Warrant or Right
Number of Shares	2,764,227	2,764,227
Weighted-Average Exercise Price	$ 2.58

Collaboration and License Agr_2

Collaboration and License Agreements (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Feb. 28, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Research and development		$ 2,706	$ 3,893	$ 4,490	$ 10,764
Scriptr Global, Inc. | Research and Development Plans and Designation of Development Candidates [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Research and development		$ 200	$ 600	$ 400	$ 1,300
Scriptr Global, Inc. | Maximum | Research and Development Plans and Designation of Development Candidates [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue recognition period	270 days
Research period	270 days

Stock-Based Compensation - Equi

Stock-Based Compensation - Equity Incentive Plans (Details) - shares		6 Months Ended
	Jun. 23, 2022	Jun. 30, 2022	Dec. 31, 2021
Class of Stock
Common stock options outstanding		5,274,668	5,202,006
Options outstanding under earlier plans		145,968
Grant of inducement stock option		325,000
2013 Stock Incentive Plan
Class of Stock
Common stock, shares reserved for future issuance	10,253,057
Common shares available for grant		4,648,994
Maximum number of additional common shares	155,968
Common stock options outstanding		4,803,700
Restricted stock units outstanding		548,491
Additional number of shares reserved for issuance	4,600,000
2017 Employee Stock Purchase Plan
Class of Stock
Common shares available for grant		720,067
Maximum number of additional common shares		600,000

Stock-Based Compensation - Empl

Stock-Based Compensation - Employee Stock Purchase Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Class of Stock
Proceeds from employee stock purchases	$ 28	$ 34
Percentage of share-based compensation expense	15%
Weighted average grant date fair value of options granted during the period (per share)	$ 0.38	$ 2.02
2017 Employee Stock Purchase Plan
Class of Stock
Common stock shares authorized for issuance under stock purchase plan	1,012,500
Common shares available for grant	720,067
Common stock share issued	76,158	13,998
Maximum | 2017 Employee Stock Purchase Plan
Class of Stock
Proceeds from employee stock purchases	$ 100	$ 100

Stock-Based Compensation - Acco

Stock-Based Compensation - Accounting for Stock-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	$ 562	$ 404	$ 1,107	$ 1,515
Research and development
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	61	53	156	433
Research and development | Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	9	3	15	15
Research and development | Equity Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	52	50	141	418
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	501	351	951	1,082
General and administrative | Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	1	1	3	3
General and administrative | Equity Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	$ 500	$ 350	$ 948	$ 1,079

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions Used in Determining Fair Value of Stock Options (Details) - $ / shares	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Stock-Based Compensation
Options to purchase common stock granted to employees and directors	660,700	833,500
Average risk free interest rate	2.30%	0.40%
Dividend rate	0%	0%
Expected lives (years)	4 years	3 years 7 months 6 days
Expected volatility	102%	87%
Weighted average exercise price (per share)	$ 0.53	$ 3.66

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended		12 Months Ended
	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Outstanding, Beginning Balance		5,202,006
Granted		660,700
Expired		(588,038)
Options, Outstanding, Ending Balance		5,274,668		5,202,006
Exercisable, Ending Balance		3,818,724
Weighted Average Exercise Price, Beginning Balance		$ 8.06
Granted, Weighted Average Exercise Price		0.53	$ 3.66
Expired, Weighted Average Exercise Price		2.87
Weighted Average Exercise Price, Ending Balance		7.70		$ 8.06
Exercisable, Weighted Average Exercise Price		$ 10.16
Outstanding, Ending balance, Weighted Average Remaining Contractual Term		6 years 7 months 6 days		5 years 10 months 24 days
Exercisable Ending Balance, Weighted Average Remaining Contractual Term		5 years 7 months 6 days
Outstanding, Intrinsic Value, Ending Balance				$ 2,949
Share based compensation arrangement by share based payment award options, annual accelerate percentage of options vested		6.25%
Share based compensation arrangement by share based payment award options, percentage of options vested every year		25%
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated vesting, number of shares	1,535,578
Unrecognized compensation cost related to nonvested stock-based compensation		$ 1,000
Weighted average remaining period over which unrecognized compensation expense will be recognized		2 years 3 months 18 days

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended			6 Months Ended
	Jul. 31, 2020	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Restricted Stock Activity, Weighted-Average Grant Date Fair Value
Share-based compensation		$ 562	$ 404		$ 1,107	$ 1,515
2013 Stock Incentive Plan
Restricted Stock Activity, Number of Shares
Nonvested shares, Ending Balance		548,491			548,491
Restricted Stock Activity, Weighted-Average Grant Date Fair Value
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant		4,648,994			4,648,994
Restricted stock units
Restricted Stock Activity, Number of Shares
Nonvested shares, Beginning Balance					68,675
Vested					(27,212)
Nonvested shares, Ending Balance		41,463			41,463
Restricted Stock Activity, Weighted-Average Grant Date Fair Value
Nonvested shares, Weighted Average Grant Date Fair Value, Beginning Balance					$ 2.30
Vested, Weighted-Average Grant Date Fair Value					2.43
Nonvested shares, Weighted Average Grant Date Fair Value, Ending Balance		$ 2.21			$ 2.21
Accelerated vesting, number of shares				137,872
Recognized compensation expense					$ 100
Unrecognized compensation expense		$ 100			$ 100
Weighted average remaining period over which unrecognized compensation expense will be recognized					1 year 2 months 12 days
Market/Performance-based Awards
Restricted Stock Activity, Number of Shares
Nonvested shares, Beginning Balance					507,028
Nonvested shares, Ending Balance		507,028			507,028
Restricted Stock Activity, Weighted-Average Grant Date Fair Value
Nonvested shares, Weighted Average Grant Date Fair Value, Beginning Balance					$ 1.54
Nonvested shares, Weighted Average Grant Date Fair Value, Ending Balance		$ 1.54			$ 1.54
Weighted average remaining period over which unrecognized compensation expense will be recognized					4 months 24 days
Requisite service period (in years)	2 years 4 months 9 days
Share-based compensation					$ 100
Unrecognized compensation expense related to the restricted stock units		$ 100			100
Additional compensation expense as a result of meeting certain achievements					$ 300

Related Party Transactions - Ov

Related Party Transactions - Overview of Related Parties (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2021
Related Party Transactions
Number of Shares			8,732,230			8,732,230
Board fees paid in stock in lieu of director board and committee fees			$ 0.1	$ 0.1
Common stock issued in lieu of board fees			91,241	47,400
Directors
Related Party Transactions
Aggregate common shares					4,608,786
Series B1 Redeemable Convertible Preferred Stock
Related Party Transactions
Conversion of preferred stock to common, shares	10,000	14,000		23,684
Baker Bros. Advisors LP
Related Party Transactions
Ownership percentage					12%
Baker Bros. Advisors LP
Related Party Transactions
Ownership percentage of new company			4%
Pillar Investment Entities
Related Party Transactions
Ownership percentage of new company			19.99%
Baker Bros. Advisors LP
Related Party Transactions
Issuance of common stock upon exercise of warrants (in shares)				2,708,812
Exercise price of warrants	$ 0.08			$ 0.08
Proceeds from exercise of warrants				$ 0.2
Aggregate common shares			2,047,180
Baker Bros. Advisors LP | Series B1 Redeemable Convertible Preferred Stock
Related Party Transactions
Conversion of preferred stock to common, shares				23,684
Baker Bros. Advisors LP | Common stock
Related Party Transactions
Shares issued on exercise of warrants during the period				2,368,400
Pillar Investment Entities
Related Party Transactions
Issuance of common stock upon exercise of warrants (in shares)				3,158,386
Exercise price of warrants	$ 0.01			$ 0.01
Cashless shares	19,052			19,052
Equity method investment beneficial ownership percentage			16%
Pillar Investment Entities | Maximum
Related Party Transactions
Proceeds from exercise of warrants				$ 0.1
Pillar Investment Entities | Warrant, Tranche One
Related Party Transactions
Exercise price of warrants			$ 2.28
Number of Shares			3,039,514
Pillar Investment Entities | Warrant, Tranche Two
Related Party Transactions
Exercise price of warrants			$ 2.58
Number of Shares			2,764,227
Pillar Investment Entities | Warrant, Tranche Three
Related Party Transactions
Exercise price of warrants			$ 2.71
Number of Shares			1,373,626
Pillar Investment Entities | Pre Funded Warrant, Tranche One
Related Party Transactions
Exercise price of warrants			$ 0.01
Number of Shares			1,533,159

Net Income (Loss) per Common _3

Net Income (Loss) per Common Share -Computation of basic and diluted net income per common share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Net income (loss) per share - Basic:
Net income (loss)	$ (5,307)	$ (4,178)	$ (7,563)	$ 115,738	$ (9,485)	$ 108,175
Less: Undistributed earnings to preferred stockholders						(2,725)
Net income (loss) applicable to common stockholders	(5,307)		(7,563)		(9,485)	105,450
Numerator for basic net income (loss) applicable to common stockholders	$ (5,307)		$ (7,563)		$ (9,485)	$ 105,450
Denominator for basic net income (loss) applicable to common stockholders	52,972		49,909		52,933	45,575
Net income (loss) income applicable to common stockholders - basic	$ (0.10)		$ (0.15)		$ (0.18)	$ 2.31
Net income (loss) per share - Diluted:
- Basic	$ (5,307)		$ (7,563)		$ (9,485)	$ 105,450
Less: Warrant revaluation gain applicable to dilutive liability-classified warrants						(6,983)
Less: Future tranche right revaluation gain applicable to dilutive liability-classified future tranche rights						(118,803)
Numerator for diluted net income (loss) applicable to common stockholders	$ (5,307)		$ (7,563)		$ (9,485)	$ (17,611)
Denominator for basic net income (loss) applicable to common stockholders	52,972		49,909		52,933	45,575
Plus: Incremental shares underlying "in the money" liability-classified warrants outstanding						496
Plus: Incremental shares underlying "in the money" liability-classified future tranche rights outstanding						8,866
Denominator for diluted net income (loss) applicable to common stockholders	52,972		49,909		52,933	54,937
Net income (loss) applicable to common stockholders - diluted	$ (0.10)		$ (0.15)		$ (0.18)	$ (0.32)

Net Income (Loss) per Common _4

Net Income (Loss) per Common Share - Antidilutive securities (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Antidilutive securities
Total antidilutive securities	14,555	14,214	14,555	14,214
Stock options
Antidilutive securities
Total antidilutive securities	5,275	4,888	5,275	4,888
Restricted stock units
Antidilutive securities
Total antidilutive securities	548	594	548	594
Common stock warrants
Antidilutive securities
Total antidilutive securities	8,732	8,732	8,732	8,732