Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 14,683	$ 19,818
Restricted cash - current	481	525
Accounts receivable, net of allowance of $640 and $672 at 2024 and 2023, respectively	2,782	3,822
Inventories, net	9,284	8,426
Prepaid expenses and other current assets	842	676
Total current assets	28,072	33,267
Property and equipment, net	3,059	3,304
Restricted cash		219
Operating lease right-of-use assets	4,767	4,982
Prepaid and other non-current assets	116	137
Total assets	36,014	41,909
Current liabilities:
Accounts payable	4,146	3,190
Accrued liabilities	2,698	2,972
Deferred revenue	4,950	6,657
Current portion of operating lease liabilities	458	428
Total current liabilities	12,252	13,247
Long-term deferred revenue	2,121	1,637
Operating lease liabilities	4,823	5,062
Other liabilities	54	43
Total liabilities	19,250	19,989
Series A - Convertible preferred stock:
Convertible preferred stock, Series A, par value $0.001; 10,000,000 shares authorized, 21,683 and 22,358 shares outstanding at 2024 and 2023, respectively	5,408	5,577
Stockholders’ equity:
Common stock, par value $0.001; 300,000,000 shares authorized, 82,990,159 and 80,949,697 shares issued at 2024 and 2023, respectively	83	81
Additional paid in capital	559,499	554,148
Treasury stock, 4,015 shares at 2024 and 2023	(206)	(206)
Accumulated deficit	(548,020)	(537,680)
Total stockholders’ equity	11,356	16,343
Total liabilities and stockholders’ equity	$ 36,014	$ 41,909