Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2020

Share-based Payment Arrangement [Abstract]

Schedule of non-cash stock-based compensation expense

Non-cash stock-based compensation expense (employee stock purchase plan, service-based stock options and restricted stock units) included in cost of goods sold, research and development expenses and selling, general and administrative expenses is summarized in the following table: 

	Three Months Ended September 30,				Nine Months Ended September 30,
(in thousands)	2020		2019		2020		2019
Cost of goods sold	$	481	$	543	$	1,541	$	1,519
Research and development	458		583		1,455		1,993
Selling, general and administrative	1,736		2,159		7,823		6,583
Total non-cash stock-based compensation expense	$	2,675	$	3,285	$	10,819	$	10,095