Build-to-Suit Lease - Narrative (Details) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended		129 Months Ended	249 Months Ended
	Jan. 31, 2017 USD ($) ft²	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2027 USD ($)	Sep. 30, 2037 USD ($)
Operating Leased Assets [Line Items]
Area of interior floor space (in sqft) | ft²	30,000
Build-to-suit facility lease obligation		$ 4.8	$ 4.8	$ 4.8
Foreign exchange loss		0.2		0.5
Scenario, Forecast
Operating Leased Assets [Line Items]
Total rent expense					$ 2.7	$ 6.4
Property, Plant and Equipment
Operating Leased Assets [Line Items]
Capitalized amount of build-to-suit asset	$ 4.2		10.0
Other Current Liabilities
Operating Leased Assets [Line Items]
Build-to-suit facility lease obligation		$ 0.2	$ 0.2	$ 0.2