CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 3,643	$ 2,788
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	488	474
Stock-based compensation	374	466
Reversal of reserve for uncertain tax positions		(1,913)
Deferred tax provision on other comprehensive income	(13)	21
Gain on sale of investments		(12)
Amortization of discount on investments	(9)	(8)
Changes in assets and liabilities:
Accounts receivable	493	1,210
Inventories		(614)
Prepaid expenses and other current assets	85	(440)
Deferred tax assets	(13)	54
Accounts payable	(37)	39
Accrued expenses	117	(56)
Accrued income taxes	(21)
Deferred revenue	(2,413)	56
Net cash provided by operating activities	2,694	2,065
Cash flows from investing activities:
Purchases of property and equipment	(82)	(117)
Sales of investments		529
Purchase of other assets		(320)
Net cash provided by (used in) investing activities	(82)	92
Cash flows from financing activities:
Proceeds from issuance of common stock	21	22
Excess tax benefits from stock-based compensation	700	413
Payments made for taxes of employees who surrendered shares related to unrestricted stock	(136)	(156)
Repurchase of common stock	(2,163)
Net cash provided by (used in) financing activities	(1,578)	279
Increase in cash and cash equivalents	1,034	2,436
Cash and cash equivalents, beginning of period	51,232	43,985
Cash and cash equivalents, end of period	52,266	46,421
Supplemental disclosure:
Cash paid for income taxes	$ 1,024	$ 356