UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Bought Deal	Public Offering	COMMON STOCK	COMMON STOCK Bought Deal	COMMON STOCK Public Offering	ADDITIONAL PAID-IN CAPITAL	ADDITIONAL PAID-IN CAPITAL Bought Deal	ADDITIONAL PAID-IN CAPITAL Public Offering	ACCUMULATED DEFICIT	ACCUMULATED OTHER COMPREHENSIVE INCOME
Beginning balance (in shares) at Dec. 31, 2019				65,378,890
Beginning balance at Dec. 31, 2019	$ 20,320			$ 7			$ 326,777			$ (306,516)	$ 52
Increase (Decrease) in Shareholders' Equity
Net Loss	(7,984)									(7,984)
Unrealized Loss on Available-for-Sale Investments	(7)										(7)
Foreign Currency Translation Adjustments	6										6
Issuance of common stock, net of offering costs (in shares)					3,670,212
Issuance of common stock, net of offering costs		$ 8,003						$ 8,003
Issuance of Warrants related to Debt Financing	501						501
Stock-based Compensation expense	935						935
Ending balance (in shares) at Mar. 31, 2020				69,049,102
Ending balance at Mar. 31, 2020	21,774			$ 7			336,216			(314,500)	51
Beginning balance (in shares) at Dec. 31, 2019				65,378,890
Beginning balance at Dec. 31, 2019	20,320			$ 7			326,777			(306,516)	52
Increase (Decrease) in Shareholders' Equity
Net Loss	(14,876)
Unrealized Loss on Available-for-Sale Investments	(13)
Foreign Currency Translation Adjustments	7
Ending balance (in shares) at Jun. 30, 2020				70,156,922
Ending balance at Jun. 30, 2020	16,212			$ 7			337,551			(321,392)	46
Beginning balance (in shares) at Mar. 31, 2020				69,049,102
Beginning balance at Mar. 31, 2020	21,774			$ 7			336,216			(314,500)	51
Increase (Decrease) in Shareholders' Equity
Net Loss	(6,892)									(6,892)
Unrealized Loss on Available-for-Sale Investments	(6)										(6)
Foreign Currency Translation Adjustments	1										1
Issuance of common stock, net of offering costs (in shares)						987,716
Issuance of common stock, net of offering costs			$ 1,978						$ 1,978
Vesting of Restricted Stock Units Issued, net of taxes withheld (in shares)				120,104
Vesting of Restricted Stock Units Issued, net of taxes withheld	(19)						(19)
Warrant Modification Expense	837						837
Stock-based Compensation expense	(1,461)						(1,461)
Ending balance (in shares) at Jun. 30, 2020				70,156,922
Ending balance at Jun. 30, 2020	$ 16,212			$ 7			337,551			(321,392)	46
Beginning balance (in shares) at Dec. 31, 2020	93,573,165			93,573,165
Beginning balance at Dec. 31, 2020	$ 34,170			$ 9			371,510			(337,406)	57
Increase (Decrease) in Shareholders' Equity
Net Loss	(7,752)									(7,752)
Unrealized Loss on Available-for-Sale Investments	(7)										(7)
Foreign Currency Translation Adjustments	3										3
Stock-based Compensation expense (in shares)				26,354
Stock-based Compensation expense	(236)						(236)
Ending balance (in shares) at Mar. 31, 2021				93,599,519
Ending balance at Mar. 31, 2021	$ 26,178			$ 9			371,274			(345,158)	53
Beginning balance (in shares) at Dec. 31, 2020	93,573,165			93,573,165
Beginning balance at Dec. 31, 2020	$ 34,170			$ 9			371,510			(337,406)	57
Increase (Decrease) in Shareholders' Equity
Net Loss	(16,152)
Unrealized Loss on Available-for-Sale Investments	(8)
Foreign Currency Translation Adjustments	$ 3
Ending balance (in shares) at Jun. 30, 2021	93,811,381			93,811,381
Ending balance at Jun. 30, 2021	$ 18,203			$ 9			371,700			(353,558)	52
Beginning balance (in shares) at Mar. 31, 2021				93,599,519
Beginning balance at Mar. 31, 2021	26,178			$ 9			371,274			(345,158)	53
Increase (Decrease) in Shareholders' Equity
Net Loss	(8,400)									(8,400)
Unrealized Loss on Available-for-Sale Investments	(1)										(1)
Foreign Currency Translation Adjustments	0
Vesting of Restricted Stock Units Issued, net of taxes withheld (in shares)				211,862
Vesting of Restricted Stock Units Issued, net of taxes withheld	(7)						(7)
Stock-based Compensation expense	$ 433						433
Ending balance (in shares) at Jun. 30, 2021	93,811,381			93,811,381
Ending balance at Jun. 30, 2021	$ 18,203			$ 9			$ 371,700			$ (353,558)	$ 52