Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 17,821,000	$ 29,523,000
Accounts receivable, net of allowance for doubtful accounts of $395 and $284 as of March 31, 2019 and December 31, 2018, respectively	4,778,000	5,704,000
Inventory	3,867,000	4,119,000
Prepaid expenses and other current assets	3,117,000	2,558,000
Total current assets	29,583,000	41,904,000
Property and equipment, net	2,832,000	2,916,000
Investment in limited liability company	1,718,000	1,843,000
Other assets	719,000	171,000
Total assets	34,852,000	46,834,000
Current liabilities:
Accounts payable	2,686,000	3,994,000
Accrued liabilities	4,802,000	6,766,000
Total current liabilities	7,488,000	10,760,000
Note payable, noncurrent portion	30,927,000	30,528,000
Other noncurrent liabilities	1,023,000	634,000
Total liabilities	39,438,000	41,922,000
Commitments and contingences (Note 8)
Stockholders’ equity (deficit):
Common stock, $0.0001 par value; 75,000,000 shares authorized as of March 31, 2019 and December 31, 2018; 46,435,802 and 46,363,945 shares issued and outstanding as of March 31, 2019 and December 31, 2018, respectively	5,000	5,000
Additional paid-in capital	160,823,000	160,292,000
Accumulated deficit	(165,414,000)	(155,385,000)
Total stockholders’ equity (deficit)	(4,586,000)	4,912,000
Total liabilities and stockholders’ equity (deficit)	$ 34,852,000	$ 46,834,000