STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net loss	$ (19,601)	$ (19,774)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	1,524	1,309
Amortization of intangible assets	1,240	1,256
Non-cash operating lease cost	517	505
Provision for expected credit losses	74	22
Write-down of inventory	320	8
Loss on disposal of property and equipment	133	27
Stock-based compensation expense	6,866	9,045
Changes in operating assets and liabilities:
Accounts receivable	(2,654)	1,332
Prepaid and other current assets	157	(1,239)
Inventories	2,333	(8,697)
Accounts payable	213	910
Accrued liabilities	75	871
Other	(166)	634
Net cash used in operating activities	(8,969)	(13,791)
Cash flows from investing activities
Purchase of property and equipment	(354)	(366)
Proceeds from sale of property and equipment		40
Net cash used in investing activities	(354)	(326)
Cash flows from financing activities
Contributions from PDL		2,366
Distributions to PDL		(1,862)
Proceeds from notes payable due to related party		12,400
Sale of common stock to PDL		16,431
Capital contribution from PDL		20,666
Proceeds from issuance of common stock under employee stock purchase plan	361
Net cash provided by financing activities	361	50,001
Net (decrease) increase in cash and cash equivalents	(8,962)	35,884
Cash and cash equivalents at beginning of the year	40,599	4,715
Cash and cash equivalents at end the year	31,637	40,599
Supplemental cash flow information
Cash paid for interest		478
Cash paid for taxes	19
Supplemental schedule of non-cash investing and financing activities
Transfer from Inventories to Equipment under lease, net	$ 4,332	3,280
Phantom stock liability settled with common stock		783
Modification of phantom stock-based awards		306
Common stock issued to extinguish Series A Preferred Stock		37,246
Common stock issued to extinguish note payable due to related party		$ 32,633