CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)
Operating activities
Net income	$ 4,736	$ 7,163
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation expense	1,762	1,573
Amortization of intangible assets	2,551	2,172
Provision for doubtful accounts	264	167
Investment discount and premium amortization	(23)	216
Stock-based compensation	6,163	3,950
Tax benefit from business acquisition	(2,415)	(9,708)
Changes in assets and liabilities:
Accounts receivable	(1,186)	(1,600)
Inventories	(3,369)	(6,940)
Restricted cash	(3)
Prepaid expenses and other current assets	1,198	1,513
Other assets	(595)	(347)
Accounts payable	875	1,752
Accrued liabilities	(1,653)	514
Deferred revenue	269	212
Other long-term liabilities	252	(462)
Net cash provided by operating activities	8,826	175
Investing activities
Purchases of available-for-sale investments	(28,933)	(1,996)
Proceeds from sales of available-for-sale investments	950
Proceeds from maturities of available-for-sale investments	20,268	27,208
Purchases of property and equipment	(1,618)	(1,171)
Business acquisitions, net of cash acquired	(7,881)	(32,891)
Net cash used in investing activities	(17,214)	(8,850)
Financing activities
Proceeds from exercise of options for common stock	7,775	711
Payments for taxes related to net share settlement of equity awards	(2,596)
Repurchase of common stock	(1,821)	(3,242)
Repayment of notes payable		(387)
Proceeds from revolving credit facility		5,000
Payment of debt issuance costs		(89)
Net cash provided by financing activities	3,358	1,993
Effect of exchange rate changes on cash and cash equivalents	280	(41)
Net change in cash and cash equivalents	(4,750)	(6,723)
Cash and cash equivalents at beginning of period	34,813	29,530
Cash and cash equivalents at end of period	30,063	22,807
Supplemental disclosure of cash flow information
Cash paid for interest	63	104
Cash paid for taxes	834	622
Supplemental schedule of non-cash investing and financing activities
Business acquisitions holdback liability	1,068
Purchases of property and equipment financed by accounts payable	178
Net unrealized (losses) gains on available-for-sale investments	$ (3)	$ 70