Share-based Compensation (Tables)

3 Months Ended

Mar. 31, 2021

Share-based Compensation

Schedule of share-based compensation expense

	Three months ended March 31,
	2021		2020
	(in thousands)
Cost of sales	$	495	$	521
Research and development		817		874
Selling, general, and administrative		1,925		2,251
Total	$	3,237	$	3,646

Summary of stock option activity

		Weighted
	Number of	Average
	Shares	Exercise Price
	(in thousands)
Balance - December 31, 2020	730		35.26
Expired or forfeited	(33)		35.37
Balance - March 31, 2021	697		35.26

Summary of non-vested restricted and performance shares activity

		Weighted
		Average
	Number of	Grant Date
	Shares	Fair Value
	(in thousands)
Balance - December 31, 2020	2,040		12.73
Granted	813		23.97
Vested	(204)		8.95
Forfeited	(39)		13.15
Balance - March 31, 2021	2,610		16.52