Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period			$ 24,914
Other comprehensive income before reclassifications	$ (11)	$ 497	(605)	$ 530
Amounts reclassified from accumulated other comprehensive income			1,183	0
Other comprehensive (loss) income	(11)	497	578	530
Balance at end of period	(26,564)		(26,564)
Foreign currency translation adjustment
Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(4,594)	(5,439)	(5,183)	(5,479)
Other comprehensive income before reclassifications	(11)	487	(605)	527
Amounts reclassified from accumulated other comprehensive income			1,183	0
Other comprehensive (loss) income	(11)	487	578	527
Balance at end of period	(4,605)	(4,952)	(4,605)	(4,952)
Unrealized loss on available for sale securities
Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	0	(7)	0	0
Other comprehensive income before reclassifications	0	10	0	3
Amounts reclassified from accumulated other comprehensive income			0	0
Other comprehensive (loss) income	0	10	0	3
Balance at end of period	0	3	0	3
Total
Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(4,594)	(5,446)	(5,183)	(5,479)
Balance at end of period	$ (4,605)	$ (4,949)	$ (4,605)	$ (4,949)