CONDENSED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 13,958	$ 20,621
Short-term investments	3,952	3,443
Accounts receivable, net of allowance of $44 and $62, respectively	4,023	4,001
Notes receivable, net of allowance of $7 and $7, respectively	329	323
Inventories	17,816	15,689
Prepaid and other current assets	2,357	2,367
Total current assets	42,435	46,444
Property and equipment, net	747	679
Equipment under lease, net	7,727	7,459
Long-term investments	1,236	492
Notes and other receivables, long-term, net of allowance of $24 and $26, respectively	1,174	1,279
Intangible assets, net	10,751	11,025
Other assets	2,064	2,207
Total assets	66,134	69,585
Current liabilities:
Accounts payable	4,120	4,007
Accrued liabilities	4,180	5,717
Deferred revenue	1,582	1,349
Operating lease liabilities	564	559
Total current liabilities	10,446	11,632
Long-term operating lease liabilities	1,607	1,750
Warrant liabilities	7,962	8,457
Other long-term liabilities	537	570
Total liabilities	20,552	22,409
Commitments and contingencies (Note 10)
Series A Redeemable Convertible Preferred Stock, par value $0.01 per share, 20 shares authorized at March 31, 2024 and December 31, 2023; 20 shares issued and outstanding at March 31, 2024 and December 31, 2023; aggregate liquidation preference of $20,000 at March 31, 2024 and December 31, 2023	13,747	13,747
Stockholders’ equity:
Preferred stock, par value $0.01 per share, 9,980 shares authorized at March 31, 2024 and December 31, 2023; no shares issued and outstanding at March 31, 2024 and December 31, 2023
Common stock, par value $0.01 per share, 150,000 shares authorized at March 31, 2024 and December 31, 2023; 11,395 and 11,327 shares issued and outstanding at March 31, 2024 and December 31, 2023, respectively	114	113
Additional paid-in capital	145,770	145,203
Accumulated other comprehensive income	(1)	4
Accumulated deficit	(114,048)	(111,891)
Total stockholders’ equity	31,835	33,429
Total liabilities, redeemable convertible preferred stock, and stockholders' equity	$ 66,134	$ 69,585