Concentrations Concentrations - Additional Information (Details)	12 Months Ended
	Dec. 31, 2015 item
Credit Concentration Risk | Cash And Cash Equivalents And Marketable Securities
Concentration Risk [Line Items]
Number of internet payment processors used	3
Customer Concentration Risk | Revenue
Concentration Risk [Line Items]
Number of advertising network partners	1
U.S. financial institutions | Credit Concentration Risk | Cash And Cash Equivalents And Marketable Securities
Concentration Risk [Line Items]
Number of financial institutions where deposits are held	6
Foreign Banks | Credit Concentration Risk | Cash And Cash Equivalents And Marketable Securities
Concentration Risk [Line Items]
Number of financial institutions where deposits are held	3