Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities:
Net loss	$ (21,279)	$ (24,010)	$ (11,935)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	3,113	1,950	1,570
Amortization expense - right-of-use assets - operating and finance leases	2,834	2,604	2,987
Stock-based compensation	11,593	7,728	6,943
Allowance for credit losses	342	40	0
Equity securities earned from research and development activities from a related party	(1,955)	(900)	0
Unrealized gain on non-marketable securities (($983) from a related party)	(1,272)	0	0
Other non-cash items	(19)	15	525
Changes in operating assets and liabilities:
Financial assets ($0, ($450) and ($332) from a related party)	(9,156)	(8,723)	(5,867)
Inventories	(196)	(593)	217
Prepaid expenses and other assets	(2,268)	(1,012)	(1,324)
Accounts payable	268	101	(428)
Accrued compensation and other accrued liabilities	6,575	6,175	2,205
Other long-term liabilities	(4,147)	(2,586)	(1,210)
Deferred revenue ($245, $0 and $0 to a related party)	1,300	2,747	(6,243)
Net cash used in operating activities	(14,267)	(16,464)	(12,560)
Investing activities:
Purchase of property and equipment	(13,828)	(3,748)	(3,730)
Proceeds from sale of property and equipment	36	0	3
Proceeds from sale of investment securities	0	0	62
Investment in non-marketable securities (($7,630) and ($1,000) in a related party)	(7,630)	(2,000)	0
Net cash used in investing activities	(21,422)	(5,748)	(3,665)
Financing activities:
Proceeds from exercises of stock options	5,180	1,323	7,099
Proceeds from issuance of common stock in connection with public offering	0	86,250	0
Costs incurred in connection with equity financing	(207)	(5,448)	(123)
Proceeds from issuance of common stock in connection with private offering	0	0	50,000
Payments of lease obligations - Finance leases	0	(60)	(242)
Recovery of short swing profit	0	0	77
Taxes paid related to net share settlement of equity awards	(1,206)	(1,257)	(2,850)
Net cash provided by financing activities	3,767	80,808	53,961
Net increase (decrease) in cash, cash equivalents and restricted cash	(31,922)	58,596	37,736
Cash, cash equivalents and restricted cash at the beginning of the year	150,817	92,221	54,485
Cash, cash equivalents and restricted cash at the end of the year	118,895	150,817	92,221
Supplemental disclosure of cash flow information:
Interest paid	14	52	49
Income taxes	102	312	5
Supplemental non-cash investing and financing activities:
Capital expenditures incurred but not yet paid	2,533	1,750	140
Cash and cash equivalents	116,797	149,117	90,498
Restricted cash, current and non-current	2,098	1,700	1,723
Total cash, cash equivalents and restricted cash at the end of the period	$ 118,895	$ 150,817	$ 92,221