Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (107,330)	$ (110,048)	$ (107,908)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	4,922	5,984	6,419
Stock-based compensation	21,608	23,871	22,805
Accretion on asset retirement obligation	95	105	63
Change in fair value of warrant liability	(2,617)	2,284	(509)
Loss on disposal of property and equipment	0	0	139
Inventory lower of cost and net realizable value adjustment	0	883	150
Provision for losses on accounts receivable	305	0	0
Amortization of debt discount and interest accrual	923	919	729
Write off of deferred financing fees	497	0	0
Impairment of ROU asset and related fixed assets	1,816	0	0
Product upgrade reserve	(1,600)	1,000	(2,294)
Changes in operating assets and liabilities:
Accounts receivable	(20,029)	(9,890)	5,048
Inventory	(1,554)	15,565	8,240
Deposits on purchased inventory	(2,706)	(2,694)	4,373
Deferred cost of revenue	(3,373)	(1,388)	(186)
Prepaid expenses and other assets	(4,144)	(5,550)	(1,356)
Accounts payable	18,402	(746)	(3,352)
Accrued expenses and other long-term liabilities	(1,796)	6,807	(292)
Customer deposits and deferred revenue	4,873	10,807	4,457
Net cash used in operating activities	(91,708)	(62,091)	(63,474)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(3,898)	(1,559)	(6,183)
Net cash used in investing activities	(3,898)	(1,559)	(6,183)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Revolving Credit Facility	5,000	0	0
Proceeds from term loan modification	77,000	0	2,000
Payment of SVB term loan	(60,000)	0	0
Payment of debt issuance costs	(1,874)	0	(815)
Proceeds from common stock public offerings, gross	0	137,884	0
Payment of offering costs related to common stock public offerings	0	(9,334)	(539)
Proceeds from employee stock purchase plan	644	550	365
Proceeds from the exercise of stock options	79	775	15
Proceeds from the exercise of warrants	0	3	0
Payments for taxes related to net share settlement of equity awards	(2,556)	(4,600)	(1,376)
Net cash provided by (used in) financing activities	18,293	125,278	(350)
NET (DECREASE) INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(77,313)	61,628	(70,007)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — BEGINNING OF PERIOD	219,808	158,180	228,187
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — END OF PERIOD	142,495	219,808	158,180
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	4,628	3,323	3,262
Cash paid for taxes	0	0	43
SUPPLEMENTAL NON-CASH INVESTING AND FINANCING ACTIVITIES:
Fair value of common stock warrants reclassed from liability to additional paid-in capital upon exercise	0	352	0
Right-of-use assets obtained in exchange for new operating lease liabilities	0	1,693	643
Transfer of property and equipment from inventory	132	576	1,698
Purchase of property and equipment in accounts payable and accrued expenses	726	82	59
Offering costs included in accounts payable and accrued expenses	$ 0	$ 25	$ 460