CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 5,959	$ 10,365
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred revenue	(12,589)	(2,690)
Depreciation	2,172	1,210
Amortization of intangibles	5,491	5,492
Amortization of premium and discount on investments, net	(966)	(562)
Stock-based compensation to employees	2,776	3,141
Stock-based compensation to Board of Directors and Scientific Advisory Board	897	709
Earnout liability recorded for Adesis acquisition		294
Deferred income tax expense	72	1,049
Retirement plan expense	1,126	1,005
Decrease (increase) in assets:
Accounts receivable	29,587	(11,327)
Inventory	(17,373)	646
Other current assets	(4,025)	616
Other assets	(177)	92
Increase (decrease) in liabilities:
Accounts payable and accrued expenses	(4,441)	(8,283)
Other current liabilities	(25)	(219)
Deferred revenue	30,331	106
Net cash provided by operating activities	38,815	1,644
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(8,733)	(631)
Purchases of investments	(123,375)	(170,136)
Proceeds from sale of investments	146,546	130,647
Net cash provided by (used in) investing activities	14,438	(40,120)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	201	159
Repurchase of common stock	(477)
Proceeds from the exercise of common stock options		24
Payment of withholding taxes related to stock-based compensation to employees	(5,832)	(3,541)
Cash dividends paid	(2,831)	(1,414)
Net cash used in financing activities	(8,939)	(4,772)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	44,314	(43,248)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	132,840	139,365
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 177,154	$ 96,117