Condensed Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (12,530)	$ (3,688)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Net accretion of discount on investment securities	(61)	0
Noncash lease expense on operating leases	541	0
Depreciation and amortization	4,863	4,010
Stock-based compensation	3,835	908
(Gain) loss on disposal of assets and other adjustments	(1)	16
Changes in operating assets and liabilities:
Accounts receivable	68	(15)
Prepaid expenses and other current assets	(153)	4
Other assets	91	(27)
Accounts payable	462	326
Accrued expenses and other current liabilities	1,187	89
Accrued VAT liability	446	19
Deferred revenue	912	1,021
Operating lease liabilities	(528)	0
Other long-term liabilities	(32)	(148)
Net cash (used in) provided by operating activities	(900)	2,515
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of marketable securities	(79,782)	0
Proceeds from disposal of property and equipment	1	13
Purchases of property and equipment, net	(516)	(2,610)
Capitalized internally-developed software costs	(1,180)	(911)
Net cash used in investing activities	(81,477)	(3,508)
CASH FLOWS FROM FINANCING ACTIVITIES
Principal payments on finance leases and lease financing obligations	(3,405)	(2,801)
Payments of deferred offering costs	(658)	(755)
Proceeds from debt facility	0	1,256
Repayment of debt facility	0	(1,256)
Proceeds from lease financing obligations	0	2,784
Proceeds from exercises of stock options	887	148
Net cash used in financing activities	(3,176)	(624)
Net decrease in cash, cash equivalents and restricted cash	(85,553)	(1,617)
Cash, cash equivalents and restricted cash at beginning of period	105,012	6,076
Cash, cash equivalents and restricted cash at end of period	19,459	4,459
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	948	849
Cash paid for income taxes	26	0
Cash paid for operating lease liabilities	598	0
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES
Stock-based compensation included in capitalized software	383	52
Accrued bonus classified as stock-based compensation	493	0
Equipment acquired through finance lease obligations	4,451	3,306
Accruals related to purchases of property and equipment	124	1,144
Lease liabilities arising from right-of-use assets upon adoption of ASC 842	5,220	0
RECONCILIATION OF CASH, CASH EQUIVALENTS AND RESTRICTED CASH
Cash and cash equivalents	19,290	4,459
Restricted cash - included in other assets	169	0
Total cash, cash equivalents and restricted cash	$ 19,459	$ 4,459