STOCK-BASED COMPENSATION

9 Months Ended

Sep. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

11. STOCK-BASED COMPENSATION

The following table summarizes the Company’s stock awards granted for each of the periods indicated:

	For the Three Months Ended September 30,								For the Nine Months Ended September 30,
	2020				2019				2020				2019
	Grants		Weighted Average Grant Date Fair Value		Grants		Weighted Average Grant Date Fair Value		Grants		Weighted Average Grant Date Fair Value		Grants		Weighted Average Grant Date Fair Value
Stock options		97,240	$	73.88		152,248	$	51.64		1,256,064	$	59.08		1,297,747	$	72.50
Restricted stock units		49,430	$	148.63		78,073	$	99.52		592,867	$	119.36		483,703	$	132.45

Stock-based Compensation Expense

For the three months ended September 30, 2020 and 2019, total stock-based compensation expense was $26.9 million and $20.6 million, respectively. For the nine months ended September 30, 2020 and 2019, total stock-based compensation expense was $78.5 million and $56.5 million, respectively. The following table summarizes stock-based compensation expense by function included within the unaudited condensed consolidated statements of operations and comprehensive loss:

		For the Three Months Ended September 30,				For the Nine Months Ended September 30,
		2020		2019		2020		2019
	(in thousands)
Research and development		$	10,645	$	6,972	$	31,034	$	18,982
Selling, general and administrative			16,258		13,665		47,509		37,556
Total stock-based compensation expense		$	26,903	$	20,637	$	78,543	$	56,538

The following table summarizes stock-based compensation expense by grant type included within the unaudited condensed consolidated statements of operations and comprehensive loss:

		For the Three Months Ended September 30,				For the Nine Months Ended September 30,
		2020		2019		2020		2019
	(in thousands)
Stock options		$	16,474	$	13,941	$	49,677	$	39,175
Restricted stock awards/units			8,950		5,233		24,047		14,333
Employee stock purchase plan			1,479		1,463		4,819		3,030
Total stock-based compensation expense		$	26,903	$	20,637	$	78,543	$	56,538