Stock-based Compensation Expense and Share Repurchase

Stock-based compensation expense

During the three months ended March 31, 2019 and 2018, the Company recognized the following stock-based compensation expense:



	Three Months Ended March 31,
	2019			2018
	(in thousands)
Stock-based compensation expense by type of award:
Restricted stock and restricted stock units (including PSUs)	$	63,510		$	50,418
Stock options	28,156			26,055
ESPP share issuances	2,577			2,128
Stock-based compensation expense related to inventories	(452		)	(465		)
Total stock-based compensation included in costs and expenses	$	93,791		$	78,136

Stock-based compensation expense by line item:
Cost of sales	$	1,338		$	813
Research and development expenses	59,715			48,488
Sales, general and administrative expenses	32,738			28,835
Total stock-based compensation included in costs and expenses	93,791			78,136
Income tax effect	(39,524		)	(21,859		)
Total stock-based compensation included in costs and expenses, net of tax	$	54,267		$	56,277

The following table sets forth the Company’s unrecognized stock-based compensation expense as of March 31, 2019, by type of award and the weighted-average period over which that expense is expected to be recognized:



	As of March 31, 2019
	Unrecognized Expense		Weighted-average Recognition Period
	(in thousands)		(in years)
Type of award:
Restricted stock and restricted stock units (including PSUs)	$	475,787	2.55
Stock options	$	193,321	2.84
ESPP share issuances	$	2,555	0.43

The following table summarizes information about stock options outstanding and exercisable as of March 31, 2019:



	Options Outstanding				Options Exercisable
Range of Exercise Prices	Number Outstanding	Weighted-average Remaining Contractual Life	Weighted-average Exercise Price		Number Exercisable	Weighted-average Exercise Price
	(in thousands)	(in years)	(per share)		(in thousands)	(per share)
$29.07–$40.00	252	1.67	$	35.87	252	$	35.87
$40.01–$60.00	437	3.20	$	50.23	437	$	50.23
$60.01–$80.00	525	5.02	$	74.83	516	$	74.82
$80.01–$100.00	2,481	6.95	$	89.20	1,315	$	89.81
$100.01–$120.00	622	5.88	$	109.32	614	$	109.24
$120.01–$140.00	773	6.36	$	130.20	653	$	130.24
$140.01–$160.00	1,287	8.82	$	155.51	333	$	155.35
$160.01–$180.00	502	8.30	$	162.94	177	$	162.95
$180.01–$187.53	1,823	9.65	$	185.29	115	$	182.72
Total	8,702	7.28	$	124.11	4,412	$	100.04

Share repurchase program

The Company’s Board of Directors approved a share repurchase program, pursuant to which the Company is authorized to repurchase up to $500.0 million of its common stock between February 1, 2018 and December 31, 2019. Under the share repurchase program, the Company is authorized to purchase shares from time to time through open market or privately negotiated transactions. Such purchases may be made pursuant to Rule 10b5-1 plans or other means as determined by the Company’s management and in accordance with the requirements of the SEC.

During the three months ended March 31, 2019 and 2018, the Company repurchased 537,018 and 67,084 shares, respectively, of its common stock under the share repurchase program for an aggregate of $98.0 million (of which $4.0 million was accrued as of March 31, 2019) and $11.3 million, respectively, including commissions and fees. As of March 31, 2019, there is a total of $52.0 million remaining for repurchases under the share repurchase program. The Company expects to fund further repurchases of its common stock through a combination of cash on hand and cash generated by operations.