STOCK-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Awards Granted

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

	For the Three Months Ended March 31,
	2020				2019
	Grants		Weighted Average Grant Date Fair Value		Grants		Weighted Average Grant Date Fair Value
Stock options		1,085,330	$	56.80		990,234	$	76.44
Restricted stock units		498,910	$	114.28		324,630	$	143.14

Summary of Stock-Based Compensation Expense by Function Included within Condensed Consolidated Statements of Operations and Comprehensive Loss

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 March 31,
		2020		2019
	(in thousands)
Research and development		$	9,249	$	5,087
Selling, general and administrative			14,775		11,052
Total stock-based compensation expense		$	24,024	$	16,139

Summary of Stock-Based Compensation Expense by Grant Type Included within Condensed Consolidated Statements of Operations and Comprehensive Loss

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 March 31,
		2020		2019
	(in thousands)
Stock options		$	15,355	$	11,457
Restricted stock awards/units			6,745		3,916
Employee stock purchase plan			1,924		766
Total stock-based compensation expense		$	24,024	$	16,139