Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustment	$ 344		$ 2,246
Net unrealized gain (loss) on investments, net of tax	(4,379)		3,521
Accumulated other comprehensive income (loss)	(4,035)		5,767	[1]
Accounting Standards Update 2016-01
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect adjustment for ASU adoption			0
Accumulated Deficit | Accounting Standards Update 2016-01
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect adjustment for ASU adoption	$ 7,200	$ 7,200	$ 7,234

[1] As adjusted to reflect the impact of the full retrospective adoption of Topic 606.