Common Stock and Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2021

Share-based Payment Arrangement [Abstract]

Summary of stock option activity

The following is a summary of stock option activity for the six months ended June 30, 2021 (in thousands, except per share data):

	Shares	Weighted- Average Exercise Price per Share
Outstanding at December 31, 2020	5,311	$	29.12
Granted	1,345	18.77
Exercised	(22)	8.80
Canceled	(216)	27.91
Outstanding at June 30, 2021	6,418	$	27.06

Schedule of restricted stock unit activity

The following is a summary of our stock award activity for the six months ended June 30, 2021 (in thousands, except per share data):

	RSUs		PSUs		Total
Outstanding at December 31, 2020	393		—		393
Granted(1)	451		492		943
Vested	(120)		—		(120)
Canceled	(35)		(26)		(61)
Outstanding at June 30, 2021	689		466		1,155
(1) Weighted-average grant date fair value	$	19.55	$	18.76	$	19.17

Stock-based compensation expense

The following table summarizes the components of total stock-based compensation expense included in our condensed consolidated statements of operations:

	Three Months Ended June 30,				Six Months Ended June 30,
(In thousands)	2021		2020		2021		2020
Research and development	$	4,525	$	3,488	$	7,824	$	6,217
Selling, general and administrative	5,001		4,815		9,800		8,480
Total	$	9,526	$	8,303	$	17,624	$	14,697

The following table summarizes stock-based compensation expense by award type included in our condensed consolidated statements of operations:

	Three Months Ended June 30,				Six Months Ended June 30,
(In thousands)	2021		2020		2021		2020
Time-based stock options and restricted stock units	$	8,734	$	6,733	16,209		12,975
Performance-based stock units	627		1,441		1,054		1,441
Employee stock purchase plan (ESPP)	165		129		361		281
Total	$	9,526	$	8,303	$	17,624	$	14,697