Cash and Cash Equivalents and Fair Value of Financial Instruments - Assets Measured at Fair Value On A Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market fund	$ 10,126	$ 10,114
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market fund	10,126	10,114
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash	30,903	72,103
Money market fund	10,126	10,114
Total cash and cash equivalents	$ 41,029	$ 82,217