Commitments and Contingencies - Lease Financing Obligation (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Lease Financing Obligation, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2017	$ 5,933
2018	6,113
2019	6,293
2020	6,477
2021	6,674
Thereafter	12,136
Total payments	43,626
Less: interest and land lease expense	(26,045)
Total payments under facility financing obligations	17,581
Property reverting to landlord	23,630
Present value of obligation	41,211
Less current portion	(1,618)
Long-term portion of obligation	$ 39,593	$ 41,210