Stock-Based Compensation - Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Stock-Based Compensation
Total stock-based compensation	$ 3.5	$ 3.3	$ 8.7	$ 8.2
Costs of product revenue
Stock-Based Compensation
Total stock-based compensation	0.5	0.5	1.3	1.2
Selling, general and administrative
Stock-Based Compensation
Total stock-based compensation	2.5	2.3	6.1	5.8
Research and development
Stock-Based Compensation
Total stock-based compensation	0.5	0.5	1.3	1.2
Mestrelab Research, S.L
Stock-Based Compensation
Total stock-based compensation	0.6		1.4
Stock options
Stock-Based Compensation
Total stock-based compensation	0.7	1.2	2.1	3.2
Restricted stock awards
Stock-Based Compensation
Total stock-based compensation	0.1	0.3	0.3	0.7
Restricted stock units
Stock-Based Compensation
Total stock-based compensation	$ 2.7	$ 1.8	$ 6.3	$ 4.3