Marketable Securities and Fair Value Measurements - Summary of Financial Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	$ 65,718	$ 66,914
Level I
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	65,718	66,914
Level II
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	0	0
Level III
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	0	0
Certificates of deposit
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	2,319	2,319
Certificates of deposit | Level I
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	2,319	2,319
Certificates of deposit | Level II
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	0	0
Certificates of deposit | Level III
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	0	0
U.S. treasuries
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	62,891	64,091
U.S. treasuries | Level I
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	62,891	64,091
U.S. treasuries | Level II
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	0	0
U.S. treasuries | Level III
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	0	0
Mutual funds
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	508	504
Mutual funds | Level I
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	508	504
Mutual funds | Level II
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	0	0
Mutual funds | Level III
Schedule Of Available For Sale Securities [Line Items]
Total Fair Value	$ 0	$ 0