Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Convertible Preferred Stock [Member]
Stockholders’ equity:
Convertible preferred stock, $0.001 par value; authorized: 5,000,000 shares; none issued and outstanding
Cash and cash equivalents	7,420	10,868
Marketable investments	35,902	37,539
Accounts receivable, net	11,181	11,669
Inventories	14,702	12,078
Other current assets and prepaid expenses	2,619	1,675
Total current assets	71,824	73,829
Property and equipment, net	1,577	1,473
Deferred tax asset	401	350
Intangibles, net	44	143
Goodwill	1,339	1,339
Other long-term assets	448	384
Total assets	75,633	77,518
Accounts payable	2,752	1,959
Accrued liabilities	13,201	13,834
Deferred revenue	8,919	8,638
Total current liabilities	24,872	24,431
Deferred revenue, net of current portion	1,685	2,287
Income tax liability	157	182
Other long-term liabilities	587	584
Total liabilities	27,301	27,484
Common stock, $0.001 par value; authorized: 50,000,000 shares; issued and outstanding: 13,143,628 and 12,980,807 shares at June 30, 2016 and December 31, 2015, respectively	13	13
Additional paid-in capital	81,309	79,782
Accumulated deficit	(32,952)	(29,672)
Accumulated other comprehensive loss	(38)	(89)
Total stockholders’ equity	48,332	50,034
Total liabilities and stockholders’ equity	$ 75,633	$ 77,518