Balance Sheet Components - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			$ 431,607
Other comprehensive income (loss) before reclassifications	$ 1,424	$ (394)	3,499	$ (5,188)
Amounts reclassified from other comprehensive income (loss), net of tax	(109)	0	(156)	0
Net current-period other comprehensive income (loss), net of tax	1,315	(394)	3,343	(5,188)
Ending balance	472,497		472,497
Foreign currency translation adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(8,765)	(7,524)	(10,764)	(2,730)
Other comprehensive income (loss) before reclassifications	1,389	(502)	3,388	(5,296)
Amounts reclassified from other comprehensive income (loss), net of tax	0	0	0	0
Net current-period other comprehensive income (loss), net of tax	1,389	(502)	3,388	(5,296)
Ending balance	(7,376)	(8,026)	(7,376)	(8,026)
Unrealized gain (loss) on interest rate swap hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	1,274	0	1,245	0
Other comprehensive income (loss) before reclassifications	35	108	111	108
Amounts reclassified from other comprehensive income (loss), net of tax	(109)	0	(156)	0
Net current-period other comprehensive income (loss), net of tax	(74)	108	(45)	108
Ending balance	1,200	108	1,200	108
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(7,491)	(7,524)	(9,519)	(2,730)
Ending balance	$ (6,176)	$ (7,918)	$ (6,176)	$ (7,918)