Fair Value Measurements (Details) - Recurring - Total - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Assets:
Restricted cash	$ 260	$ 260
Total assets	50,478	73,922
Cash
Assets:
Cash and cash equivalents	2,755	1,520
Money market funds
Assets:
Cash and cash equivalents	47,463	72,142
Level I
Assets:
Restricted cash	260	260
Total assets	50,478	73,922
Level I | Cash
Assets:
Cash and cash equivalents	2,755	1,520
Level I | Money market funds
Assets:
Cash and cash equivalents	$ 47,463	$ 72,142