Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2021

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 product sales, 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)	2021		2020		2021		2020
Cost of product sales	$	1,114	$	481	$	3,313	$	1,541
Research and development	1,126		458		3,222		1,455
Selling, general and administrative	6,356		1,736		19,946		7,823
Total non-cash stock-based compensation expense	$	8,596	$	2,675	$	26,481	$	10,819