CONDENSED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 28,984	$ 31,637
Accounts receivable, net of allowance of $34 and $47, respectively	3,585	4,638
Notes receivable, net of allowance of $180 and $61, respectively	194	350
Inventories	4,279	6,488
Prepaid and other current assets	1,508	1,700
Total current assets	38,550	44,813
Property and equipment, net	755	756
Equipment under lease, net	7,289	6,690
Notes and other receivables, long-term, net of allowance of $1 and $2, respectively	62	121
Intangible assets, net	10,561	10,870
Other assets	3,082	3,215
Total assets	60,299	66,465
Current liabilities:
Accounts payable	2,852	2,694
Accrued liabilities	3,406	4,604
Deferred revenue	989	904
Operating lease liabilities	516	512
Total current liabilities	7,763	8,714
Long-term operating lease liabilities	2,672	2,803
Other long-term liabilities	52	69
Total liabilities	10,487	11,586
Commitments and contingencies (Note 8)
Stockholders’ equity:
Preferred stock, par value $0.01 per share, 10,000 shares authorized at March 31, 2022 and December 31, 2021; no shares issued and outstanding at March 31, 2022 and December 31, 2021
Common stock, par value $0.01 per share, 150,000 shares authorized at March 31, 2022 and December 31, 2021; 10,985 and 10,990 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively	110	110
Additional paid-in capital	133,970	132,363
Accumulated deficit	(84,268)	(77,594)
Total stockholders’ equity	49,812	54,879
Total liabilities and stockholders’ equity	$ 60,299	$ 66,465