Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 9,653	$ 12,689
Accounts receivable, net of allowance for doubtful accounts of $6 at March 31, 2018 and December 31, 2017, respectively	127	95
Inventory	148	191
Prepaid expenses	277	340
Total current assets	10,205	13,315
Property and equipment, net	152	169
Other assets	54	54
Total assets	10,411	13,538
Current liabilities:
Accounts payable	738	902
Accrued expenses and other current liabilities	1,323	1,263
Deferred revenue	60	167
Total current liabilities	2,121	2,332
Deferred rent	83	81
Total liabilities	2,204	2,413
Stockholders’ equity:
Preferred stock, $0.001 par value, 25,000,000 shares authorized; no shares issued and outstanding as of March 31, 2018 and December 31, 2017
Common stock, $0.001 par value, 100,000,000 shares authorized as of March 31, 2018 and December 31, 2017 respectively; 38,241,244 and 38,218,660 shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively	38	38
Additional paid-in capital	84,157	83,537
Accumulated deficit	(75,988)	(72,450)
Total stockholders’ equity	8,207	11,125
Total liabilities and stockholders’ equity	$ 10,411	$ 13,538