SHARE BASED COMPENSATION (Tables)

6 Months Ended

Jun. 30, 2020

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, 2020:

	Number of Restricted Stock Units	Weighted Average Grant Date Fair Value
Unvested December 31, 2019	763,728	$	19.64
Granted	637,113	15.51
Vested	(173,117)	21.25
Forfeited/canceled	(68,414)	18.58
Unvested June 30, 2020	1,159,310	$	17.19

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, 2020:

	Number of Restricted Stock Units	Weighted Average Grant Date Fair Value
Unvested December 31, 2019	233,500	$	20.90
Granted	150,000	15.46
Vested	(33,250)	25.75
Forfeited/canceled	(31,125)	17.56
Unvested June 30, 2020	319,125	$	18.16

Schedule of stock option issuances and balances outstanding

The following table summarizes stock option activity during the six months ended June 30, 2020:

	Shares Underlying Options	Weighted Average Exercise Price	Weighted Average Remaining Contractual Life (years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2019	7,371,733	$19.52	6.63	$	4,906
Granted	1,390,125	$15.48
Exercised	(35,042)	$12.31
Forfeited/canceled	(377,953)	$18.96
Outstanding at June 30, 2020	8,348,863	$18.90	6.79	$	28,920

Schedule of share based compensation expenses

The following table sets forth total share-based compensation for the three and six months ended June 30, 2020 and 2019 (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
Research and development	$	2,332	$	1,896	$	4,458	$	3,566
Selling, general & administrative	3,622		3,852		7,406		8,702
Total	$	5,954	$	5,748	$	11,864	$	12,268