Organization and Basis of Presentation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands							1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 28, 2022	Dec. 23, 2021	Jul. 16, 2021	Jun. 05, 2020	Dec. 30, 2019	Nov. 29, 2019	Mar. 31, 2022	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Each warrant exercisable shares										10,687,912
Purchase price / Exercise price of warrant										$ 1.26	$ 11.06
Accumulated deficit										$ 246,452	$ 197,789
Cash and cash equivalents										29,988	$ 35,042
Restructuring charges, number of workforce headcount reduction percentage						38.00%
Subsequent Event
Class Of Stock [Line Items]
Directors' & Officers' run-off insurance amount							$ 6,800
Run off period							6 years
Restructuring charges, number of workforce headcount reduction percentage							40.00%
Loan and Security Agreement | Pontifax
Class Of Stock [Line Items]
Outstanding principal balance										$ 10,000
Loan and Security Agreement | Pontifax | Subsequent Event
Class Of Stock [Line Items]
Principal prepayments								$ 5,000
Outstanding principal balance							$ 5,000	$ 5,000
At Market Issuance Sales Agreement
Class Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares			4,081,338
B. Riley ATM Agreement | At Market Issuance Sales Agreement
Class Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares										4,081,338
Weighted average price of common stock shares sold and issued										$ 1.11
Net proceeds after deducting offering costs										$ 4,200
Updated B. Riley ATM Agreement. | At Market Issuance Sales Agreement
Class Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares		6,804,888
Weighted average price of common stock shares sold and issued		$ 0.62
Net proceeds after deducting offering costs		$ 4,100
Updated B. Riley ATM Agreement. | At Market Issuance Sales Agreement | Subsequent Event
Class Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares								6,804,888
Weighted average price of common stock shares sold and issued								$ 0.62
Net proceeds after deducting offering costs								$ 4,100
Cowen ATM Agreement
Class Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares									6,058,318
Weighted average price of common stock shares sold and issued									$ 1.99
Net proceeds after deducting offering costs					$ 2,600				$ 11,700
Retention Plan | Subsequent Event
Class Of Stock [Line Items]
Retention agreement received salary adjustment percentage	6.50%
RSUs granted	3,163,000
Stock-based award, vesting period	3 years
Employees retention payment	$ 3,000
Percentage of amount employee to repay for resigns or terminated	50.00%
Direct Offering
Class Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares			17,416,096	7,317,074
Maximum aggregate warrant to purchase number of shares of common stock			10,678,872
Difference in combined price of each share of common stock and accompanying warrant and purchase price of prefunded warrant per share			$ 0.01
Gross proceeds of the transaction			$ 28,000
Each warrant exercisable shares			1
Purchase price / Exercise price of warrant			$ 1.25
Warrant exercisable date			Jul. 16, 2026
Combined price of each share of common stock and accompanying warrant to purchase one-half price per share			$ 1.311
Net proceeds after deducting offering costs			$ 25,400	$ 13,700
Direct Offering | Pre-Funded Warrant
Class Of Stock [Line Items]
Maximum aggregate warrant to purchase number of shares of common stock			3,941,648
Purchase price of warrant			$ 1.301
Each warrant exercisable shares			1
Purchase price / Exercise price of warrant			$ 0.01
Warrant exercisable date			Jul. 16, 2021