UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS’ (DEFICIT) EQUITY Statement - USD ($) shares in Thousands, $ in Thousands	Total	Ordinary shares	Preferred Stock [Member]	Additional paid-in capital	Accumulated deficit	Accumulated other comprehensive (loss) income	Treasury shares
Beginning balance (in shares) at Dec. 31, 2018		42,720					5,407
Beginning balance at Dec. 31, 2018	$ 2,780	$ 427		$ 433,756	$ (357,989)	$ (23,416)	$ (49,998)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(13,018)				(13,018)
Other comprehensive income (loss)	213					213
Vesting of restricted shares (in shares)		1
Vesting of restricted shares	0
Employee share purchase plan share issuance (in shares)		42
Employee share purchase plan share issuance	92			92
Stock-based compensation expense	351			351
Ending balance (in shares) at Mar. 31, 2019		42,763					5,407
Ending balance at Mar. 31, 2019	(9,582)	$ 427		434,199	(371,007)	(23,203)	$ (49,998)
Beginning balance (in shares) at Dec. 31, 2018		42,720					5,407
Beginning balance at Dec. 31, 2018	2,780	$ 427		433,756	(357,989)	(23,416)	$ (49,998)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(21,623)
Ending balance (in shares) at Jun. 30, 2019		42,763					5,407
Ending balance at Jun. 30, 2019	(17,777)	$ 427		434,254	(379,612)	(22,848)	$ (49,998)
Beginning balance (in shares) at Mar. 31, 2019		42,763					5,407
Beginning balance at Mar. 31, 2019	(9,582)	$ 427		434,199	(371,007)	(23,203)	$ (49,998)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(8,605)				(8,605)
Other comprehensive income (loss)	355					355
Stock-based compensation expense	55			55
Ending balance (in shares) at Jun. 30, 2019		42,763					5,407
Ending balance at Jun. 30, 2019	(17,777)	$ 427		434,254	(379,612)	(22,848)	$ (49,998)
Beginning balance (in shares) at Dec. 31, 2019		42,927	0				5,407
Beginning balance at Dec. 31, 2019	(29,199)	$ 429	$ 0	434,391	(391,215)	(22,806)	$ (49,998)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(865)
Other comprehensive income (loss)	(821)					(821)
Exercise of stock options (in shares)		146
Exercise of stock options	1,389	$ 2		1,387
February 2020 private placement (in shares)		8,680	488
February 2020 private placement	60,733	$ 87	$ 5	60,641
Vesting of restricted shares (in shares)		19
Vesting of restricted shares	0
Employee share purchase plan share issuance (in shares)		40
Employee share purchase plan share issuance	88			88
Stock-based compensation expense	742			742
Ending balance (in shares) at Mar. 31, 2020		51,812	488				5,407
Ending balance at Mar. 31, 2020	32,067	$ 518	$ 5	497,249	(392,080)	(23,627)	$ (49,998)
Beginning balance (in shares) at Dec. 31, 2019		42,927	0				5,407
Beginning balance at Dec. 31, 2019	(29,199)	$ 429	$ 0	434,391	(391,215)	(22,806)	$ (49,998)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	30,009
Ending balance (in shares) at Jun. 30, 2020		63,537	488				5,407
Ending balance at Jun. 30, 2020	182,125	$ 635	$ 5	615,207	(361,206)	(22,518)	$ (49,998)
Beginning balance (in shares) at Mar. 31, 2020		51,812	488				5,407
Beginning balance at Mar. 31, 2020	32,067	$ 518	$ 5	497,249	(392,080)	(23,627)	$ (49,998)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	30,874
Other comprehensive income (loss)	1,109					1,109
Exercise of stock options (in shares)		95
Exercise of stock options	393	$ 1		392
February 2020 private placement	(94)			(94)
Employee share purchase plan share issuance	33			33
Stock-based compensation expense	769			769
May 2020 public offering (in shares)		11,630
May 2020 public offering	116,974	$ 116		116,858
Ending balance (in shares) at Jun. 30, 2020		63,537	488				5,407
Ending balance at Jun. 30, 2020	$ 182,125	$ 635	$ 5	$ 615,207	$ (361,206)	$ (22,518)	$ (49,998)