Stock-Based Compensation (Tables)

6 Months Ended

Jun. 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 June 30,				Six Months Ended June 30,
(in thousands)	2021		2020		2021		2020
Cost of product sales	$	1,287	$	568	$	2,199	$	997
Research and development	1,234		484		2,096		1,060
Selling, general and administrative	8,345		3,325		13,590		6,087
Total non-cash stock-based compensation expense	$	10,866	$	4,377	$	17,885	$	8,144