Summary of Significant Accounting Policies - Schedule of Useful Lives of Property and Equipment (Detail)	12 Months Ended
	Dec. 31, 2016
Computer Equipment [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Useful lives of property and equipment	3 years
Computer Equipment [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Useful lives of property and equipment	5 years
Office Equipment, Furniture and Fixtures [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Useful lives of property and equipment	3 years
Office Equipment, Furniture and Fixtures [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Useful lives of property and equipment	5 years
Software [Member]
Property Plant And Equipment [Line Items]
Useful lives of property and equipment	3 years
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Useful lives of property and equipment	Shorter of useful life or lease term