Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Public Offering [Member] Common Stock [Member]	Public Offering [Member] Preferred Stock [Member]	Public Offering [Member] Treasury Stock [Member]	Public Offering [Member] Additional Paid-in Capital [Member]	Public Offering [Member] Retained Earnings [Member]	Public Offering [Member] AOCI Attributable to Parent [Member]	Public Offering [Member]	Common Stock [Member]	Preferred Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2019								20,691	0	0
Balance at Dec. 31, 2019								$ 21	$ 0	$ 0	$ 720,484	$ (663,600)	$ (1,370)	$ 55,535
Stock-based compensation								$ 0	$ 0	$ 0	1,923	0	0	1,923
Issuance of common stock, net of issuance costs (in shares)	14,122	7,937	0					7,030	0	0
Issuance of common stock, net of issuance costs	$ 14	$ 79	$ 0	$ 13,432	$ 0	$ 0	$ 13,525	$ 7	$ 0	$ 0	11,205	0	0	11,212
Award of restricted stock units (in shares)								141	0	0
Award of restricted stock units								$ 0	$ 0	$ 0	0	0	0	0
Return of common stock to pay withholding taxes on restricted stock (in shares)								0	0	28
Return of common stock to pay withholding taxes on restricted stock								$ 0	$ 0	$ 0	(33)	0	0	(33)
Cancellation of treasury stock (in shares)								0	0	(28)
Cancellation of treasury stock								$ 0	$ 0	$ 0	0	0	0	0
Other comprehensive loss								0	0	0	0	0	(872)	(872)
Net loss								$ 0	$ 0	$ 0	0	(16,598)	0	(16,598)
Conversion of preferred stock to common stock (in shares)								3,053	(3,053)	0
Conversion of preferred stock to common stock								$ 3	$ (30)	$ 0	27	0	0	0
Exchange of shares for Series B Warrants (in shares)								2,041	0	0
Exchange of shares for Series B Warrants								$ 2	$ 0	$ 0	2,468	0	0	2,470
Balance (in shares) at Mar. 31, 2020								47,078	4,884	0
Balance at Mar. 31, 2020								$ 47	$ 49	$ 0	749,506	(680,198)	(2,242)	67,162
Balance (in shares) at Dec. 31, 2019								20,691	0	0
Balance at Dec. 31, 2019								$ 21	$ 0	$ 0	720,484	(663,600)	(1,370)	55,535
Net loss														(45,521)
Balance (in shares) at Sep. 30, 2020								99,879	0	0
Balance at Sep. 30, 2020								$ 100	$ 0	$ 0	770,368	(709,120)	821	62,169
Balance (in shares) at Dec. 31, 2019								20,691	0	0
Balance at Dec. 31, 2019								$ 21	$ 0	$ 0	720,484	(663,600)	(1,370)	55,535
Exercise of stock options and warrants (in shares)								4,900
Balance (in shares) at Dec. 31, 2020								116,231	0	0
Balance at Dec. 31, 2020								$ 116	$ 0	$ 0	781,397	(722,912)	2,968	61,569
Balance (in shares) at Mar. 31, 2020								47,078	4,884	0
Balance at Mar. 31, 2020								$ 47	$ 49	$ 0	749,506	(680,198)	(2,242)	67,162
Stock-based compensation								$ 0	$ 0	$ 0	1,933	0	0	1,933
Exercise of stock options and warrants (in shares)								4,913	0	0
Exercise of stock options and warrants								$ 5	$ 0	$ 0	3,335	0	0	3,340
Award of restricted stock units (in shares)								28	0	0
Award of restricted stock units								$ 0	$ 0	$ 0	0	0	0	0
Other comprehensive loss								0	0	0	0	0	962	962
Net loss								$ 0	$ 0	$ 0	0	(13,840)	0	(13,840)
Conversion of preferred stock to common stock (in shares)								4,884	(4,884)	0
Conversion of preferred stock to common stock								$ 5	$ (49)	$ 0	44	0	0	0
Balance (in shares) at Jun. 30, 2020								56,903	0	0
Balance at Jun. 30, 2020								$ 57	$ 0	$ 0	754,818	(694,038)	(1,280)	59,557
Stock-based compensation								$ 0	$ 0	$ 0	1,944	0	0	1,944
Issuance of common stock, net of issuance costs (in shares)								42,857	0	0
Issuance of common stock, net of issuance costs								$ 43	$ 0	$ 0	13,606	0	0	13,649
Award of restricted stock units (in shares)								119	0	0
Award of restricted stock units								$ 0	$ 0	$ 0	0	0	0	0
Other comprehensive loss								0	0	0	0	0	2,101	2,101
Net loss								$ 0	$ 0	$ 0	0	(15,082)	0	(15,082)
Balance (in shares) at Sep. 30, 2020								99,879	0	0
Balance at Sep. 30, 2020								$ 100	$ 0	$ 0	770,368	(709,120)	821	62,169
Balance (in shares) at Dec. 31, 2020								116,231	0	0
Balance at Dec. 31, 2020								$ 116	$ 0	$ 0	781,397	(722,912)	2,968	61,569
Stock-based compensation								$ 0	$ 0	$ 0	1,786	0	0	1,786
Issuance of common stock, net of issuance costs (in shares)								70,666	0	0
Issuance of common stock, net of issuance costs								$ 71	$ 0	$ 0	129,251	0	0	129,322
Exercise of stock options and warrants (in shares)								45,114	0	0
Exercise of stock options and warrants								$ 45	$ 0	$ 0	32,687	0	0	32,732
Award of restricted stock units (in shares)								706	0	0
Award of restricted stock units								$ 1	$ 0	$ 0	0	0	0	1
Return of common stock to pay withholding taxes on restricted stock (in shares)								0	0	67
Return of common stock to pay withholding taxes on restricted stock								$ 0	$ 0	$ 0	(214)	0	0	(214)
Cancellation of treasury stock (in shares)								0	0	(67)
Cancellation of treasury stock								$ 0	$ 0	$ 0	0	0	0	0
Other comprehensive loss								0	0	0	0	0	(1,938)	(1,938)
Net loss								$ 0	$ 0	$ 0	0	(17,340)	0	(17,340)
Balance (in shares) at Mar. 31, 2021								232,717	0	0
Balance at Mar. 31, 2021								$ 233	$ 0	$ 0	944,907	(740,252)	1,030	205,918
Balance (in shares) at Dec. 31, 2020								116,231	0	0
Balance at Dec. 31, 2020								$ 116	$ 0	$ 0	781,397	(722,912)	2,968	61,569
Net loss														(46,581)
Balance (in shares) at Sep. 30, 2021								234,370	0	0
Balance at Sep. 30, 2021								$ 234	$ 0	$ 0	950,242	(769,493)	518	181,501
Balance (in shares) at Mar. 31, 2021								232,717	0	0
Balance at Mar. 31, 2021								$ 233	$ 0	$ 0	944,907	(740,252)	1,030	205,918
Stock-based compensation								$ 0	$ 0	$ 0	1,842	0	0	1,842
Issuance of common stock, net of issuance costs (in shares)								332	0	0
Issuance of common stock, net of issuance costs								$ 0	$ 0	$ 0	992	0	0	992
Exercise of stock options and warrants (in shares)								508	0	0
Exercise of stock options and warrants								$ 0	$ 0	$ 0	337	0	0	337
Award of restricted stock units (in shares)								674	0	0
Award of restricted stock units								$ 1	$ 0	$ 0	0	0	0	1
Return of common stock to pay withholding taxes on restricted stock (in shares)								0	0	246
Return of common stock to pay withholding taxes on restricted stock								$ 0	$ 0	$ 0	(829)	0	0	(829)
Cancellation of treasury stock (in shares)								0	0	(246)
Cancellation of treasury stock								$ 0	$ 0	$ 0	0	0	0	0
Other comprehensive loss								0	0	0	0	0	472	472
Net loss								$ 0	$ 0	$ 0	0	(13,172)	0	(13,172)
Balance (in shares) at Jun. 30, 2021								234,231	0	0
Balance at Jun. 30, 2021								$ 234	$ 0	$ 0	947,249	(753,424)	1,502	195,561
Stock-based compensation								$ 0	$ 0	$ 0	2,961	0	0	2,961
Issuance of common stock, net of issuance costs (in shares)								21	0	0
Issuance of common stock, net of issuance costs								$ 0	$ 0	$ 0	47	0	0	47
Exercise of stock options and warrants (in shares)								5	0	0
Exercise of stock options and warrants								$ 0	$ 0	$ 0	2	0	0	2
Award of restricted stock units (in shares)								113	0	0
Award of restricted stock units								$ 0	$ 0	$ 0	0	0	0	0
Return of common stock to pay withholding taxes on restricted stock (in shares)								0	0	6
Return of common stock to pay withholding taxes on restricted stock								$ 0	$ 0	$ 0	(17)	0	0	(17)
Cancellation of treasury stock (in shares)								0	0	(6)
Cancellation of treasury stock								$ 0	$ 0	$ 0	0	0	0	0
Other comprehensive loss								0	0	0	0	0	(984)	(984)
Net loss								$ 0	$ 0	$ 0	0	(16,069)	0	(16,069)
Balance (in shares) at Sep. 30, 2021								234,370	0	0
Balance at Sep. 30, 2021								$ 234	$ 0	$ 0	$ 950,242	$ (769,493)	$ 518	$ 181,501