Stock-Based Compensation - Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Stock-Based Compensation
Total stock-based compensation	$ 3.0	$ 2.7
Cost of revenues
Stock-Based Compensation
Total stock-based compensation	0.5	0.4
Selling, general and administrative
Stock-Based Compensation
Total stock-based compensation	2.0	1.9
Research and development
Stock-Based Compensation
Total stock-based compensation	0.5	0.4
Mestrelab Research, S.L
Stock-Based Compensation
Total stock-based compensation	0.3	0.4
Stock options
Stock-Based Compensation
Total stock-based compensation	0.4	0.7
Restricted stock awards
Stock-Based Compensation
Total stock-based compensation		0.1
Restricted stock units
Stock-Based Compensation
Total stock-based compensation	$ 2.6	$ 1.9