CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 1,949	$ 1,314
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Amortization of deferred revenue	(2,032)	(1,177)
Depreciation	902	702
Amortization of intangibles	2,750	2,750
Amortization of premium and discount on investments, net	(297)	(135)
Stock-based compensation to employees	2,830	1,715
Stock-based compensation to Board of Directors and Scientific Advisory Board	408	366
Deferred income tax benefit	(169)	334
Retirement plan benefit expense	1,029	592
Decrease (increase) in assets:
Accounts receivable	3,863	3,911
Inventories	(1,961)	(1,858)
Other current assets	(2,296)	703
Other assets	(472)	20
(Decrease) increase in liabilities:
Accounts payable and accrued expenses	(9,134)	(8,584)
Other current liabilities	590	(55)
Deferred revenue	2,250	46,382
Net cash provided by operating activities	210	46,980
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(516)	(1,950)
Purchases of investments	(193,929)	(51,957)
Proceeds from sale of investments	208,571	90,876
Net cash provided by investing activities	14,126	36,969
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from issuance of common stock	99	90
Proceeds from the exercise of common stock options	151	702
Payment of withholding taxes related to stock-based employee compensation	(2,008)	(4,970)
Net cash used in financing activities	(1,758)	(4,178)
INCREASE IN CASH AND CASH EQUIVALENTS	12,578	79,771
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	97,513	45,418
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 110,091	$ 125,189