Condensed Consolidated Statements of Cash Flows (Statement) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (53,407)	$ (57,719)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,643	3,171
Stock-based compensation	10,133	14,949
Accretion on asset retirement obligation	46	61
Change in fair value of warrant liabilities	(4,885)	4,701
Impairment of right-of-use asset and related fixed assets	1,816	0
Amortization of debt discount and interest accrual	477	471
Product upgrade reserve	(1,600)	1,000
Changes in operating assets and liabilities:
Accounts receivable	(11,355)	(3,647)
Inventory	256	4,763
Deposits on purchased inventory	(1,782)	(1,595)
Deferred cost of revenue	1,774	755
Prepaid expenses and other assets	(4,630)	(5,397)
Accounts payable	7,611	(2,508)
Accrued expenses and other long-term liabilities	(10,104)	(1,374)
Customer deposits and deferred revenue	8,674	2,057
Net cash used in operating activities	(54,333)	(40,312)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(2,666)	(568)
Net cash used in investing activities	(2,666)	(568)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from common stock public offering, gross	0	57,385
Payment of offering costs related to common stock public offering	0	(3,991)
Proceeds from term loan modification	2,000	0
Payment of debt issuance costs	(914)	0
Proceeds from the exercise of stock options	67	184
Proceeds from the exercise of warrants	0	2
Proceeds from employee stock purchase plan	322	264
Payments for taxes related to net share settlement of equity awards	2,094	2,759
Net cash (used in) provided by financing activities	(619)	51,085
NET (DECREASE) INCREASE CASH DURING THE PERIOD	(57,618)	10,205
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — BEGINNING OF PERIOD	219,808	158,180
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — END OF PERIOD	162,190	168,385
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	1,695	1,648
Cash paid for income taxes	0	0
SUPPLEMENTAL NON-CASH INVESTING AND FINANCING ACTIVITIES:
Fair value of common stock warrants reclassified from liability to additional paid-in capital upon exercise	0	351
Transfer of property and equipment from inventory and deferred cost of revenue	19	0
Purchases of property and equipment in accounts payable and accrued liabilities	$ 161	$ 351