Accrued Expenses and Other Current Liabilities - Severance Costs (Details) - Reductions in force - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Severance costs	$ 1,700
Accrued expense	1,020	$ 485
Accrued expenses and other current liabilities
Restructuring Cost and Reserve [Line Items]
Accrued expense	1,000
Sales and Marketing
Restructuring Cost and Reserve [Line Items]
Severance costs	700
Product Development
Restructuring Cost and Reserve [Line Items]
Severance costs	600
Service Costs
Restructuring Cost and Reserve [Line Items]
Severance costs	300
General and Administrative
Restructuring Cost and Reserve [Line Items]
Severance costs	$ 100