CONDENSED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 35,866	$ 40,599
Accounts receivable, net of allowance of $21 and $19, respectively	2,105	2,012
Notes receivable, net of allowance of $9 and $9, respectively	427	444
Inventories	13,021	13,473
Prepaid and other current assets	1,824	1,857
Total current assets	53,243	58,385
Property and equipment, net	744	832
Equipment under lease, net	3,773	3,583
Notes and other receivables, long-term, net of allowance of $7 and $9, respectively	364	452
Intangible assets, net	11,797	12,110
Other assets	3,622	3,758
Total assets	73,543	79,120
Current liabilities:
Accounts payable	1,702	2,481
Accrued liabilities	2,761	4,570
Deferred revenue	967	923
Other current liabilities	498	493
Total current liabilities	5,928	8,467
Long-term operating lease liabilities	3,189	3,314
Other long-term liabilities	97	129
Total liabilities	9,214	11,910
Commitments and contingencies (Note 9)
Stockholders’ equity:
Preferred stock, par value $0.01 per share, 10,000 shares authorized at March 31, 2021 and December 31, 2020; no shares issued and outstanding at March 31, 2021 and December 31, 2020
Common stock, par value $0.01 per share, 150,000 shares authorized at March 31, 2021 and December 31, 2020; 10,933 shares issued and outstanding at March 31, 2021 and December 31, 2020	109	109
Additional paid-in capital	127,395	125,094
Accumulated deficit	(63,175)	(57,993)
Total stockholders’ equity	64,329	67,210
Total liabilities and stockholders’ equity	$ 73,543	$ 79,120