Condensed Consolidated Statements of 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]	Cumulative Effect, Period of Adoption, Adjustment [Member] Common Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Preferred Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Treasury Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Additional Paid-in Capital [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] AOCI Attributable to Parent [Member]	Cumulative Effect, Period of Adoption, Adjustment [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, 2018															16,642	0	0
Balance at Dec. 31, 2018								$ 0	$ 0	$ 0	$ (7)	$ 7	$ 0	$ 0	$ 17	$ 0	$ 0	$ 676,572	$ (509,406)	$ 1,338	$ 168,521
Stock-based compensation															$ 0	$ 0	$ 0	2,981	0	0	2,981
Award of restricted stock units (in shares)															47	0	0
Award of restricted stock units															$ 0	$ 0	$ 0	1	0	0	1
Return of common stock to pay withholding taxes on restricted stock (in shares)															0	0	15
Return of common stock to pay withholding taxes on restricted stock															$ 0	$ 0	$ 0	(499)	0	0	(499)
Cancellation of treasury stock (in shares)															0	0	(15)
Cancellation of treasury stock															$ 0	$ 0	$ 0	0	0	0	0
Other comprehensive income (loss)															0	0	0	0	0	(1,949)	(1,949)
Net loss															$ 0	$ 0	$ 0	0	(22,525)	0	(22,525)
Balance (in shares) at Mar. 31, 2019															16,701	0	0
Balance at Mar. 31, 2019															$ 17	$ 0	$ 0	679,284	(531,924)	(611)	146,766
Balance (in shares) at Dec. 31, 2018															16,642	0	0
Balance at Dec. 31, 2018								0	0	0	(7)	7	0	0	$ 17	$ 0	$ 0	676,572	(509,406)	1,338	168,521
Net loss																					(42,696)
Balance (in shares) at Jun. 30, 2019															16,740	0	0
Balance at Jun. 30, 2019															$ 17	$ 0	$ 0	682,936	(552,095)	629	131,487
Balance (in shares) at Dec. 31, 2018															16,642	0	0
Balance at Dec. 31, 2018								$ 0	$ 0	$ 0	$ (7)	$ 7	$ 0	$ 0	$ 17	$ 0	$ 0	676,572	(509,406)	1,338	168,521
Exercise of stock options and warrants (in shares)															12	0	0
Exercise of stock options and warrants															$ 0	$ 0	$ 0	236	0	0	236
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
Balance (in shares) at Mar. 31, 2019															16,701	0	0
Balance at Mar. 31, 2019															$ 17	$ 0	$ 0	679,284	(531,924)	(611)	146,766
Stock-based compensation															$ 0	$ 0	$ 0	3,355	0	0	3,355
Award of restricted stock units (in shares)															14	0	0
Award of restricted stock units															$ 0	$ 0	$ 0	0	0	0	0
Other comprehensive income (loss)															0	0	0	0	0	1,240	1,240
Net loss															$ 0	$ 0	$ 0	0	(20,171)	0	(20,171)
Exercise of stock options and warrants (in shares)															25	0	0
Exercise of stock options and warrants															$ 0	$ 0	$ 0	297	0	0	297
Balance (in shares) at Jun. 30, 2019															16,740	0	0
Balance at Jun. 30, 2019															$ 17	$ 0	$ 0	682,936	(552,095)	629	131,487
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
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
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)
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
Conversion of preferred stock to common stock (in shares)															7,900	7,900
Net loss																					(30,438)
Exercise of stock options and warrants (in shares)															4,900
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
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
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
Award of restricted stock units (in shares)															28	0	0
Award of restricted stock units															$ 0	$ 0	$ 0	0	0	0	0
Other comprehensive income (loss)															0	0	0	0	0	962	962
Net loss															$ 0	$ 0	$ 0	0	(13,840)	0	(13,840)
Exercise of warrants (in shares)															4,913	0	0
Exercise of warrants															$ 5	$ 0	$ 0	3,335	0	0	3,340
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