Marketable Securities and Fair Value Measurements - Summary of Financial Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	$ 52,840	$ 52,907
Level I
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	52,840	52,906
Level II
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value		1
Certificates of Deposit
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	2,318	2,318
Certificates of Deposit | Level I
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	2,318	2,318
U.S. Treasuries
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	50,015	50,082
U.S. Treasuries | Level I
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	50,015	50,082
Mutual Funds
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	507	506
Mutual Funds | Level I
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	$ 507	506
Interest Rate Cap
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value		1
Interest Rate Cap | Level II
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value		$ 1