Commitments and Contingencies - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) facility	Mar. 31, 2016 USD ($)
Long-term Purchase Commitment [Line Items]
Number of leased facilities | facility	2
Operating lease payments	$ 74	$ 72
Colorado
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding, amount	18
Wells Fargo Bank, N.A. | Colorado
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding, amount	$ 18