Commitments and Contingencies - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended
	Jan. 31, 2017	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Commitments And Contingencies [Line Items]
Non-cancelable operating lease agreements expiration		2024-12
Rent expense		$ 900,000		$ 1,100,000
Restructuring charge related to facility exit costs			$ 2,100,000
Restructuring accrual balance		$ 1,600,000	$ 1,900,000
Computer Equipment | Promissory Note
Commitments And Contingencies [Line Items]
Debt instrument, used to finance	$ 800,000
Debt instrument, frequency of payment		quarterly
Debt instrument, maturity period	3 years
Debt instrument, remaining amount		$ 600,000
Marketing Arrangements
Commitments And Contingencies [Line Items]
Unconditional purchase commitments		$ 6,100,000
Unconditional purchase commitment year		2034
Unconditional purchase commitment term		20 years
Open Purchase Commitments
Commitments And Contingencies [Line Items]
Software license fees and marketing services		$ 6,100,000
NEW YORK
Commitments And Contingencies [Line Items]
Non-cancelable operating lease agreements expiration		2024-12