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 stock (in shares)	14,122	7,937	0					7,030	0	0
Issuance of stock	$ 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 income (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
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
Stock-based compensation								$ 0	$ 0	$ 0	1,786	0	0	1,786
Issuance of stock (in shares)								70,666	0	0
Issuance of stock								$ 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 income (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