Condensed Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 16,707	$ 16,410
Accounts receivable, net of allowance for doubtful accounts of $232 and $260 at March 31, 2019 and December 31, 2018, respectively	1,112	1,154
Right of use asset	1,313
Inventories	3,955	3,422
Prepaid expenses and other current assets	1,026	635
Total current assets	24,113	21,621
Property and equipment, net	2,140	2,078
Total assets	26,253	23,699
Current liabilities:
Accounts payable	969	1,148
Accrued compensation	1,016	1,197
Accrued expenses and other current liabilities	906	1,449
Leasehold liability	1,313
Borrowings	7,837	7,486
Preferred stock dividends payable	895	2,918
Total current liabilities	12,936	14,198
Other long-term liabilities	38	41
Total liabilities	12,974	14,239
Commitments and contingencies (Note 6)
Stockholders’ equity:
Convertible preferred stock issuable in series, par value of $0.001 Shares authorized: 5,000,000 at March 31, 2019 and December 31, 2018 Shares issued and outstanding: 44,923 and 45,671 at March 31, 2019 and December 31, 2018, respectively; aggregate liquidation preference of $45,640 and $44,718 at March 31, 2019 and December 31, 2018, respectively
Common stock, par value of $0.001; Shares authorized: 100,000,000 at March 31, 2019 and December 31, 2018 Common stock, par value of $0.001, Shares authorized: 100,000,000 at at December 31, 2018 and 2017 Shares issued and outstanding: 60,052,992 and 34,921,999 at March 31, 2019 and December 31, 2018, respectively	59	34
Additional paid-in capital	347,160	338,311
Accumulated deficit	(333,940)	(328,885)
Total stockholders’ equity	13,279	9,460
Total liabilities and stockholders’ equity	$ 26,253	$ 23,699