Stock-Based Compensation Expense (Tables)

9 Months Ended

Sep. 30, 2019

Share-based Payment Arrangement [Abstract]

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2019		2018		2019		2018
Cost of sales	$	346	$	241	$	953	$	657
Research and development		277		141		750		412
Selling, general and administrative		2,003		1,291		5,212		3,425
Stock-based compensation expense before taxes	$	2,626	$	1,673	$	6,915	$	4,494

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

	Nine Months Ended
	September 30,
	2019	2018
Risk-free interest rate	1.39% - 2.56%	2.63% - 2.77%
Expected option term	3 - 5 years	5.0 years
Expected dividend yield	—	—
Expected price volatility	28.66% - 35.79%	34.06% - 34.32%