CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net loss	$ (6,674)	$ (5,182)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	541	328
Amortization of intangible assets	309	313
Non-cash operating lease cost	130	129
Provision for expected credit losses	134
Write-down of inventory		4
Loss on disposal of property and equipment		120
Stock-based compensation expense	1,607	2,320
Changes in operating assets and liabilities:
Accounts receivable	1,037	(95)
Prepaid and other current assets	192	33
Inventories	1,116	12
Accounts payable	158	(778)
Accrued liabilities	(1,198)	(1,828)
Other	41	5
Net cash used in operating activities	(2,607)	(4,619)
Cash flows from investing activities
Purchase of property and equipment	(46)	(114)
Net cash used in investing activities	(46)	(114)
Net decrease in cash and cash equivalents	(2,653)	(4,733)
Cash and cash equivalents at beginning of the period	31,637	40,599
Cash and cash equivalents at end of the period	28,984	35,866
Supplemental schedule of non-cash investing and financing activities
Transfer from Inventories to Equipment under lease, net	1,060	$ 435
Transfer from Inventories to Property and equipment, net	$ 34