Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	$ 32,118	$ 32,252	$ 34,052	$ 34,172
Balance at end of period	30,641	33,131	30,641	33,131
Foreign currency translation
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(1,224)	(950)	(1,285)	(772)
Total other comprehensive (loss) income	(337)	(263)	(276)	(441)
Balance at end of period	(1,561)	(1,213)	(1,561)	(1,213)
Available-for-sale marketable securities
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	0	1	0	4
Other comprehensive (loss) income	0	0	0	(3)
Balance at end of period	0	1	0	1
Total accumulated other comprehensive loss
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(1,224)	(949)	(1,285)	(768)
Balance at end of period	$ (1,561)	$ (1,212)	$ (1,561)	$ (1,212)