Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	$ 2,323	$ 2,787
Adjustments to reconcile net income to net cash provided by operations:
Depreciation and amortization expense	947	1,033
Amortization of deferred rent	(39)	(47)
Stock-based compensation expense	319	455
Provision for (recoveries of) doubtful accounts, net	34	(6)
Write-down of inventory to net realizable value	130	130
Loss on disposal of assets	54
Tax benefit from exercise of stock options	(676)	(29)
Deferred income taxes	130	(13)
Changes in operating assets and liabilities:
Receivables	(609)	1,319
Inventories	548	(1,439)
Prepaid expenses and other assets	24	(377)
Accounts payable	(719)	(19)
Accrued liabilities	36	(1,072)
Income taxes payable	335	969
Deferred product revenue	229	(222)
Other long-term liabilities	(53)	(604)
Net cash provided by operating activities	3,013	2,865
Cash flows from investing activities:
Purchase of property and equipment	(402)	(182)
Proceeds from maturities and sales of marketable securities	3,405	4,197
Purchases of marketable securities	(4,250)	(3,204)
Net cash provided by (used in) investing activities	(1,247)	811
Cash flows from financing activities:
Proceeds from the exercise of stock options	476	90
Repurchase and cancellation of stock options	(1,752)
Tax benefits from exercise of stock options	676	29
Dividends paid	(924)	(319)
Repurchase and cancellation of stock	(4,115)
Net cash used in financing activities	(5,639)	(200)
Effect of exchange rate changes on cash and cash equivalents	6	(43)
Net increase (decrease) in cash and cash equivalents	(3,867)	3,433
Cash and cash equivalents at the beginning of the period	13,412	7,440
Cash and cash equivalents at the end of the period	9,545	10,873
Supplemental disclosure of cash flow information:
Cash paid for income taxes	$ 715	$ 2,280