CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net loss	$ (82,035)	$ (108,825)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,061	2,019
Charges (credits) to provision for doubtful accounts	445	(182)
Inventory charge	502	5,965
Debt financing fees	2,681	692
Non-cash operating lease expense	434	770
Share-based compensation	5,467	5,369
Changes in operating assets and liabilities:
Accounts receivable	(1,544)	6,287
Inventory	(83)	(4,277)
Prepaid and other current assets	365	4,448
Accounts payable	(6,503)	(1,911)
Accrued expenses and other current liabilities	12,940	(5,420)
Other non-current liabilities	358
Total adjustments	17,123	13,760
Net cash used in operating activities	(64,912)	(95,065)
Cash flows from investing activities:
Payment of patent related costs	(423)	(816)
Purchase of fixed assets	(104)	(26)
Net cash used in investing activities	(527)	(842)
Cash flows from financing activities:
Proceeds from sale of common stock, net of costs	151,062
Proceeds from exercise of options and warrants	299	166
Proceeds from sale of common stock related to employee stock purchase plan	134
Repayments of debt	(50,000)
Borrowings of debt		50,000
Payment of debt financing fees	(5,118)	(1,250)
Net cash provided by financing activities	96,377	48,916
Net increase in cash	30,938	(46,991)
Cash, beginning of period	80,486	160,830
Cash, end of period	111,424	113,839
Supplemental disclosure of cash flow information:
Interest paid	$ 14,284	$ 12,032