Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance at Dec. 31, 2018	$ 276	$ 303,015	$ (80,762)	$ (8,523)	$ 214,006
Exercise of share options	2	1,800	0	0	1,802
Share-based compensation expense	0	845	0	0	845
Tax on vesting of restricted share units	0	(145)	0	0	(145)
Other comprehensive income (loss)	0	0	0	1,167	1,167
Net income (loss)	0	0	(1,496)	0	(1,496)
Other comprehensive income (loss)	0	0	0	1,167	1,167
Net income (loss)	0	0	(1,496)	0	(1,496)
Balance at Mar. 31, 2019	278	305,515	(82,258)	(7,356)	216,179
Balance at Dec. 31, 2018	276	303,015	(80,762)	(8,523)	214,006
Other comprehensive income (loss)					(1,902)
Net income (loss)					(189)
Other comprehensive income (loss)					(1,902)
Net income (loss)					(189)
Balance at Sep. 30, 2019	278	306,601	(81,485)	(10,425)	214,969
Balance at Mar. 31, 2019	278	305,515	(82,258)	(7,356)	216,179
Exercise of share options	2	1,531	0	0	1,533
Share-based compensation expense	0	846	0	0	846
Tax on vesting of restricted share units	0	(10)	0	0	(10)
Other comprehensive income (loss)	0	0	0	(1,355)	(1,355)
Net income (loss)	0	0	590	0	590
Other comprehensive income (loss)	0	0	0	(1,355)	(1,355)
Net income (loss)	0	0	590	0	590
Balance at Jun. 30, 2019	280	307,882	(81,668)	(8,711)	217,783
Exercise of share options	0	593	0	0	593
Share-based compensation expense	0	983	0	0	983
Tax on vesting of restricted share units	0	(68)	0	0	(68)
Other comprehensive income (loss)	0	0	0	(1,714)	(1,714)
Ordinary shares repurchased	(2)	(2,789)	(534)	0	(3,325)
Net income (loss)	0	0	717	0	717
Other comprehensive income (loss)	0	0	0	(1,714)	(1,714)
Net income (loss)	0	0	717	0	717
Balance at Sep. 30, 2019	278	306,601	(81,485)	(10,425)	214,969
Balance at Dec. 31, 2019	276	304,909	(84,033)	(7,461)	213,691
Exercise of share options	0	1	0	0	1
Share-based compensation expense	0	957	0	0	957
Tax on vesting of restricted share units	0	(155)	0	0	(155)
Other comprehensive income (loss)	0	0	0	(2,727)	(2,727)
Ordinary shares repurchased	(4)	(6,138)	(1,590)	0	(7,732)
Net income (loss)	0	0	(6,027)	0	(6,027)
Other comprehensive income (loss)	0	0	0	(2,727)	(2,727)
Net income (loss)	0	0	(6,027)	0	(6,027)
Balance at Mar. 31, 2020	272	299,574	(91,650)	(10,188)	198,008
Balance at Dec. 31, 2019	276	304,909	(84,033)	(7,461)	213,691
Other comprehensive income (loss)					(1,415)
Net income (loss)					(15,861)
Other comprehensive income (loss)					(1,415)
Net income (loss)					(15,861)
Balance at Sep. 30, 2020	272	301,347	(101,484)	(8,876)	191,259
Balance at Mar. 31, 2020	272	299,574	(91,650)	(10,188)	198,008
Exercise of share options	0	57	0	0	57
Share-based compensation expense	0	610	0	0	610
Tax on vesting of restricted share units	0	(10)	0	0	(10)
Other comprehensive income (loss)	0	0	0	(87)	(87)
Net income (loss)	0	0	(9,685)	0	(9,685)
Other comprehensive income (loss)	0	0	0	(87)	(87)
Net income (loss)	0	0	(9,685)	0	(9,685)
Balance at Jun. 30, 2020	272	300,231	(101,335)	(10,275)	188,893
Exercise of share options	0	41	0	0	41
Share-based compensation expense	0	1,101	0	0	1,101
Tax on vesting of restricted share units	0	(26)	0	0	(26)
Other comprehensive income (loss)	0	0	0	1,399	1,399
Net income (loss)	0	0	(149)	0	(149)
Other comprehensive income (loss)	0	0	0	1,399	1,399
Net income (loss)	0	0	(149)	0	(149)
Balance at Sep. 30, 2020	$ 272	$ 301,347	$ (101,484)	$ (8,876)	$ 191,259