Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Shares [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive income (loss) [Member]	Accumulated Currency Translation Effect [Member]
Beginning balance at Dec. 31, 2018	$ 138,872	$ 3,770	$ 779,465	$ (923)	$ (626,976)	$ (477)	$ (15,987)
Beginning balance (Shares) at Dec. 31, 2018		30,157,777
Net (loss)	(172,011)				(172,011)
Other comprehensive income	(373)					585	(958)
Issuance of ordinary shares	208,766	$ 1,875	206,891
Issuance of ordinary shares (Shares)		16,870,733
Treasury shares	693			693
Share-based payments	17,239		17,239
Ending balance at Dec. 31, 2019	193,186	$ 5,645	1,003,595	(230)	(798,988)	108	(16,945)
Ending balance (Shares) at Dec. 31, 2019		47,028,510
Net (loss)	(159,555)				(159,555)
Other comprehensive income	23,480					376	23,104
Issuance of ordinary shares	150,449	$ 873	149,576
Issuance of ordinary shares (Shares)		7,900,677
Treasury shares	(939)			(939)
Share-based payments	(1,130)		(1,130)
Ending balance at Dec. 31, 2020	$ 205,491	$ 6,518	$ 1,152,042	$ (1,169)	$ (958,543)	$ 484	$ 6,158
Ending balance (Shares) at Dec. 31, 2020		54,929,187