Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$ 9,930	$ 13,418	$ 6,099
Adjustments to reconcile net income to net cash flows provided by operating activities, net of acquisitions:
Depreciation	3,335	3,661	3,547
Amortization	3,011	1,522	1,082
Stock-based compensation	2,482	1,614	1,459
Loss on write-down or disposal of long-lived assets	45	8	4
Deferred income taxes	(398)	(7,176)	(113)
Excess tax benefits related to stock option exercises	(853)
(Increase) decrease, net of effect of acquisitions, in:
Accounts receivable, net	5,371	(4,606)	2,804
Inventories	(1,063)	3,429	(1,493)
Prepaid expenses and other	898	1,989	1,677
Increase (decrease), net of effect of acquisitions, in:
Accounts payable	44	657	(177)
Deferred revenue	(704)	(788)	(1,867)
Accrued and other long-term liabilities	2,105	(1,483)	(2,434)
Net cash provided by operating activities	24,203	12,245	10,588
Cash flows from investing activities:
Purchase of marketable securities	(2,947)	(15,312)	(9,145)
Proceeds from sale of marketable securities	5,596	16,357	8,302
Decrease in restricted cash	952	33	425
Purchase of fixed assets	(4,856)	(1,692)	(1,767)
Proceeds from sale of fixed assets and assets held for sale	34	16	25
Cash paid for acquisitions, net of cash acquired	(1,528)	(13,253)
Net cash used in investing activities	(2,749)	(13,851)	(2,160)
Cash flows from financing activities:
Principal payments on capital lease obligations		(2)	(16)
Withholding taxes paid on net settlement of vested restricted stock units	(699)	(476)	(339)
Excess tax benefits related to stock option exercises	853
Proceeds from issuances of common stock	2,101	1,582	398
Cash paid for repurchase of common stock	(1,070)	(58)	(1,332)
Net cash provided by (used in) financing activities	1,185	1,046	(1,289)
Effect of exchange rate changes on cash and cash equivalents	(1,704)	(195)	132
Increase (decrease) in cash and cash equivalents	20,935	(755)	7,271
Cash and cash equivalents:
Beginning of year	17,172	17,927	10,656
End of year	38,107	17,172	17,927
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net	1,282	566	1,552
Supplemental disclosure of non-cash information:
Common stock issued in connection with acquisitions		14,524
Fair value of assets acquired from acquisitions, net of cash		35,209
Liabilities assumed from acquisitions		4,893
Payable for fixed assets	525
Transfer from (to) inventory to (from) fixed assets	$ (182)	$ (94)	$ 1,038