Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Accumulated earnings of foreign subsidiaries		$ 913
Valuation allowance released as a result of acquisition to recognize income tax benefit		328	$ 0	$ 6,821
Valuation allowance movements		18,240	$ 795
CrowdStar
Income Tax Contingency [Line Items]
Valuation allowance released as a result of acquisition to recognize income tax benefit	$ 328
Federal Tax
Income Tax Contingency [Line Items]
Net operating loss carryforwards		158,531
U S State
Income Tax Contingency [Line Items]
Net operating loss carryforwards		97,627
Federal Research And Development Credits | Research and Development Tax Credit Carryforward
Income Tax Contingency [Line Items]
Tax credit carryforward amount		11,158
California Research And Development Tax Credit | Research and Development Tax Credit Carryforward
Income Tax Contingency [Line Items]
Tax credit carryforward amount		12,941
Foreign
Income Tax Contingency [Line Items]
Tax credit carryforward amount		$ 6,320