SHARE-BASED COMPENSATION (Tables)

6 Months Ended

Jun. 30, 2021

Equity [Abstract]

Schedule of service based restricted stock activity

The following table summarizes the Company’s service based restricted stock unit activity during the six months ended June 30, 2021:

	Number of Restricted Stock Units	Weighted Average Grant Date Fair Value
Unvested December 31, 2020	1,109,942	$	17.84
Granted	800,797	25.49
Vested	(365,492)	17.96
Forfeited/canceled	(77,784)	21.42
Unvested June 30, 2021	1,467,463	$	21.80

Schedule of performance based restricted stock activity

The following table summarizes the Company’s performance based restricted stock unit activity during the six months ended June 30, 2021:

	Number of Restricted Stock Units	Weighted Average Grant Date Fair Value
Unvested December 31, 2020	167,500	$	16.48
Granted	—	—
Vested	(75,000)	15.46
Forfeited/canceled	—	—
Unvested June 30, 2021	92,500	$	17.31

Schedule of stock option issuances and balances outstanding

The following table summarizes stock option activity during the six months ended June 30, 2021:

	Shares Underlying Options	Weighted Average Exercise Price	Weighted Average Remaining Contractual Life (years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020	8,242,996	$18.97	6.43	$	71,641
Granted	1,518,307	26.36
Exercised	(206,380)	14.90
Forfeited/canceled	(225,803)	22.98
Outstanding at June 30, 2021	9,329,120	$20.17	6.42	$	4,922

Schedule of share based compensation expenses

The following table sets forth total share-based compensation for the three and six months ended June 30, 2021 and 2020 (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development	$	2,845	$	2,332	$	5,847	$	4,458
Selling, general & administrative	4,665		3,622		9,357		7,406
Total	$	7,510	$	5,954	$	15,204	$	11,864