Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (loss)	Accumulated Deficit	Total
Balance at beginning of period at Dec. 31, 2018	$ 120	$ 214,694	$ 4,293	$ (96,470)	$ 122,637
Balance (in shares) at Dec. 31, 2018	11,969,928
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense		1,823			1,823
Exercise of options and vesting of RSUs		1,290			1,290
Exercise of options and vesting of RSUs (in shares)	68,908
Other comprehensive income (loss)			2,298		2,298
Net loss				(16,657)	(16,657)
Balance at end of period at Mar. 31, 2019	$ 120	217,807	6,591	(113,127)	111,391
Balance (in shares) at Mar. 31, 2019	12,038,836
Balance at beginning of period at Dec. 31, 2018	$ 120	214,694	4,293	(96,470)	122,637
Balance (in shares) at Dec. 31, 2018	11,969,928
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)					2,289
Net loss					(33,285)
Balance at end of period at Jun. 30, 2019	$ 126	240,734	6,582	(129,755)	117,687
Balance (in shares) at Jun. 30, 2019	12,685,326
Balance at beginning of period at Mar. 31, 2019	$ 120	217,807	6,591	(113,127)	111,391
Balance (in shares) at Mar. 31, 2019	12,038,836
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense		2,049			2,049
Exercise of options and vesting of RSUs		110			110
Exercise of options and vesting of RSUs (in shares)	9,123
Issuance of common stock, net of costs	$ 6	20,768			20,774
Issuance of common stock (in shares)	637,367
Other comprehensive income (loss)			(9)		(9)
Net loss				(16,628)	(16,628)
Balance at end of period at Jun. 30, 2019	$ 126	240,734	6,582	(129,755)	117,687
Balance (in shares) at Jun. 30, 2019	12,685,326
Balance at beginning of period at Dec. 31, 2019	$ 127	245,769	6,452	(159,187)	93,161
Balance (in shares) at Dec. 31, 2019	12,749,443
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense		2,381			2,381
Exercise of options and vesting of RSUs		94			94
Exercise of options and vesting of RSUs (in shares)	37,662
Issuance of common stock, net of costs	$ 22	42,977			42,999
Issuance of common stock (in shares)	2,190,750
Other comprehensive income (loss)			6,287		6,287
Net loss				(31,488)	(31,488)
Balance at end of period at Mar. 31, 2020	$ 149	291,221	12,739	(190,675)	113,434
Balance (in shares) at Mar. 31, 2020	14,977,855
Balance at beginning of period at Dec. 31, 2019	$ 127	245,769	6,452	(159,187)	93,161
Balance (in shares) at Dec. 31, 2019	12,749,443
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)					(278)
Net loss					(52,091)
Balance at end of period at Jun. 30, 2020	$ 149	294,075	6,174	(211,278)	89,120
Balance (in shares) at Jun. 30, 2020	14,989,021
Balance at beginning of period at Mar. 31, 2020	$ 149	291,221	12,739	(190,675)	113,434
Balance (in shares) at Mar. 31, 2020	14,977,855
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense		2,603			2,603
Exercise of options and vesting of RSUs		138			138
Exercise of options and vesting of RSUs (in shares)	11,166
Issuance of warrants		113			113
Other comprehensive income (loss)			(6,565)		(6,565)
Net loss				(20,603)	(20,603)
Balance at end of period at Jun. 30, 2020	$ 149	$ 294,075	$ 6,174	$ (211,278)	$ 89,120
Balance (in shares) at Jun. 30, 2020	14,989,021