CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (172,415,000)	$ (183,524,000)	$ (176,145,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	4,093,000	4,067,000	1,392,000
Charges to provision for doubtful accounts	533,000	238,000	318,000
Inventory charge	1,082,000	7,205,000	0
Debt financing fees	5,689,000	2,532,000	856,000
Share-based payment compensation costs	18,125,000	10,679,000	10,682,000
Write-off of patent and trademark	0	1,132,000	79,000
Loss of extinguishment of debt			10,058,000
Other	720,000	1,541,000	1,074,000
Changes in operating assets and liabilities:
Accounts receivable	(4,327,000)	(8,224,000)	(13,651,000)
Inventory	(711,000)	(3,337,000)	(8,593,000)
Prepaid and other current assets	(3,005,000)	3,209,000	(1,734,000)
Accounts payable	(750,000)	1,887,000	(3,563,000)
Accrued expenses and other current liabilities	6,134,000	2,904,000	13,675,000
Other non-current liabilities	2,139,000	220,000	(166,000)
Total adjustments	29,722,000	24,053,000	10,427,000
Net cash used in operating activities	(142,693,000)	(159,471,000)	(165,718,000)
Cash flows from investing activities:
Payment for patent related costs	(2,189,000)	(1,391,000)	(1,442,000)
Payment for intellectual property license			(20,000,000)
Purchase of fixed assets	(34,000)	(207,000)	(2,450,000)
Net cash used in investing activities	(2,223,000)	(1,598,000)	(23,892,000)
Cash flows from financing activities:
Proceeds from sale of common stock, net of costs	184,115,000	31,703,000	77,031,000
Proceeds from exercise of options and warrants	322,000	272,000	109,000
Proceeds from sale of common stock related to employee stock purchase plan	233,000
Repayments of debt	(50,000,000)		(81,661,000)
Borrowings of debt		50,000,000	200,000,000
Payment of debt financing fees	(5,118,000)	(1,250,000)	(6,652,000)
Net cash provided by financing activities	129,552,000	80,725,000	188,827,000
Net decrease in cash	(15,364,000)	(80,344,000)	(783,000)
Cash, beginning of period	80,486,000	160,830,000	161,613,000
Cash, end of period	65,122,000	80,486,000	160,830,000
Supplemental disclosure of cash flow information:
Interest paid	$ 25,068,000	25,849,000	$ 17,788,000
Supplemental disclosure of noncash financing activities:
Warrants issued in relation to debt financing agreement		$ 7,668,000