Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	$ 32,983	$ 34,507	$ 34,052	$ 34,172
Balance at end of period	32,118	32,252	32,118	32,252
Foreign currency translation
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(1,181)	(353)	(1,285)	(768)
Total other comprehensive (loss) income	(43)	(596)	61	(181)
Balance at end of period	(1,224)	(949)	(1,224)	(949)
Available-for-sale marketable securities
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	0	3	0	4
Other comprehensive (loss) income	0	(3)	0	(4)
Balance at end of period	0	0	0	0
Total accumulated other comprehensive loss
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(1,181)	(353)	(1,285)	(768)
Balance at end of period	$ (1,224)	$ (949)	$ (1,224)	$ (949)