Commitments and Contingencies - Narrative (Details) ft² in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) ft² building	Jun. 30, 2016 USD ($)
Other Commitments [Line Items]
Number of buildings occupied | building			2
Monthly rent expense under operating lease | $	$ 1.1	$ 1.0	$ 2.2	$ 1.9
Lease One
Other Commitments [Line Items]
Leased square feet			67
Lease renewal term			5 years
Lease Two
Other Commitments [Line Items]
Leased square feet			129
Lease renewal term			10 years