Condensed Consolidated Statements of Stockholders' (Deficit) Equity (Unaudited) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	ADDITIONAL PAID-IN CAPITAL Cumulative Effect, Period of Adoption, Adjustment	ACCUMULATED OTHER COMPREHENSIVE LOSS	ACCUMULATED DEFICIT	ACCUMULATED DEFICIT Cumulative Effect, Period of Adoption, Adjustment
Beginning balance (in shares) at Dec. 31, 2020			46,821,644
Beginning balance at Dec. 31, 2020	$ 23,968		$ 47	$ 1,103,074		$ (52)	$ (1,079,101)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options and warrants (in shares)			62,016
Issuance of common stock upon exercise of stock options and warrants	26			26
Issuance of common stock for restricted stock awards, net (in shares)			10,162
Issuance of common stock for restricted stock awards, net	(1,127)			(1,127)
Stock-based compensation	8,741			8,741
Other comprehensive income (loss)	(12)					(12)
Net loss	(41,964)						(41,964)
Ending balance (in shares) at Mar. 31, 2021			46,893,822
Ending balance at Mar. 31, 2021	(10,368)		$ 47	1,110,714		(64)	(1,121,065)
Beginning balance (in shares) at Dec. 31, 2020			46,821,644
Beginning balance at Dec. 31, 2020	23,968		$ 47	1,103,074		(52)	(1,079,101)
Ending balance (in shares) at Dec. 31, 2021			48,444,473
Ending balance at Dec. 31, 2021	$ (17,333)	$ (76,704)	$ 48	1,136,656	$ (124,666)	(126)	(1,153,911)	$ 47,962
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2020-06
Issuance of common stock for restricted stock awards, net (in shares)			191,227
Issuance of common stock for restricted stock awards, net	$ (358)			(358)
Stock-based compensation	4,878			4,878
Other comprehensive income (loss)	(304)					(304)
Net loss	(35,891)						(35,891)
Ending balance (in shares) at Mar. 31, 2022			48,635,700
Ending balance at Mar. 31, 2022	$ (125,712)		$ 48	$ 1,016,510		$ (430)	$ (1,141,840)