Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income [Member]
Beginning balances at Dec. 31, 2017	$ 119,309	$ 32	$ 186,522	$ (68,203)	$ 958
Beginning balance, shares at Dec. 31, 2017		30,509,522
Issuance of common stock upon at the market offerings, net	493		493
Issuance of common stock upon at The market offering, net, shares		46,900
Issuance of common stock for settlement of RSUs, shares		11,250
Net Issuance of common stock upon cashless exercise of stock options, shares		28,655
Issuance of common stock upon exercise of stock options	3		3
Issuance of common stock upon exercise of stock options, shares		6,000
Issuance of common stock upon exercise of warrants	18		18
Issuance of common stock upon exercise of warrants, Shares		2,039
Stock-based compensation	412		412
Foreign exchange translation adjustment	341				341
Unrealized gain (loss) on short-term investments	(24)				(24)
Net loss incurred	(26,849)			(26,849)
Ending balance at Mar. 31, 2018	93,703	$ 32	187,448	(95,052)	1,275
Ending balance, shares at Mar. 31, 2018		30,604,366
Beginning balances at Dec. 31, 2018	108,219	$ 36	237,702	(129,719)	200
Beginning balance, shares at Dec. 31, 2018		35,146,096
Issuance of common stock upon at the market offerings, net	4,890		4,890
Issuance of common stock upon at The market offering, net, shares		647,426
Issuance of common stock for settlement of RSUs, shares		13,125
Issuance of common stock upon exercise of stock options	6		6
Issuance of common stock upon exercise of stock options, shares		23,593
Stock-based compensation	1,000		1,000
Foreign exchange translation adjustment	(225)				(225)
Unrealized gain (loss) on short-term investments	26				26
Net loss incurred	(12,112)			(12,112)
Ending balance at Mar. 31, 2019	$ 101,804	$ 36	$ 243,598	$ (141,831)	$ 1
Ending balance, shares at Mar. 31, 2019		35,830,240