Balance Sheet Components - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 773,242	$ 588,640	$ 679,617	$ 554,341
Other comprehensive income (loss) before reclassifications	(2,825)	(817)	(2,979)	(2,163)
Amounts reclassified from other comprehensive income (loss), net of tax	0	(324)	(568)	(808)
Net current-period other comprehensive income (loss), net of tax	(2,825)	(1,141)	(3,547)	(2,971)
Ending balance	807,533	619,238	807,533	619,238
Foreign currency translation adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(11,576)	(8,896)	(11,274)	(6,954)
Other comprehensive income (loss) before reclassifications	(2,825)	(907)	(3,127)	(2,849)
Amounts reclassified from other comprehensive income (loss), net of tax	0	0	0	0
Net current-period other comprehensive income (loss), net of tax	(2,825)	(907)	(3,127)	(2,849)
Ending balance	(14,401)	(9,803)	(14,401)	(9,803)
Unrealized gain (loss) on interest rate swap hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	0	953	420	841
Other comprehensive income (loss) before reclassifications	0	90	148	686
Amounts reclassified from other comprehensive income (loss), net of tax	0	(324)	(568)	(808)
Net current-period other comprehensive income (loss), net of tax	0	(234)	(420)	(122)
Ending balance	0	719	0	719
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(11,576)	(7,943)	(10,854)	(6,113)
Ending balance	$ (14,401)	$ (9,084)	$ (14,401)	$ (9,084)