Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities
Net loss	$ (80,652)	$ (97,316)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation	3,161	3,186
Amortization and accretion	14,948	13,358
Stock-based compensation	16,745	20,705
Other non-cash	1,320	7
Changes in operating assets and liabilities
Accounts receivable, net	(3,129)	(4,724)
Inventory	(3,173)	2,397
Prepaid, current and other assets	(2,532)	(861)
Accounts payable, accrued expenses and other current liabilities	4,082	1,484
Operating lease liabilities	(2,934)	(2,929)
Deferred revenue	1,970	0
Net cash used in operating activities	(50,194)	(64,693)
Cash flows from investing activities
Purchase of available-for-sale investments	(73,006)	(43,455)
Proceeds from sales and maturities of investments	52,988	118,357
Purchase of property, plant and equipment	(1,377)	(1,690)
Net cash (used in) provided by activities	(21,395)	73,212
Cash flows from financing activities
Proceeds from loan	0	8,274
Repayment of loan	0	(8,274)
Payments related to issuance of stock for stock-based compensation arrangements, net	(25)	(1,160)
Net cash used in financing activities	(25)	(1,160)
Net change in cash and cash equivalents	(71,614)	7,359
Cash and cash equivalents, at beginning of period	151,570	143,940
Cash and cash equivalents, at end of period	79,956	151,299
Non-cash investing and financing activities
Purchase of property, plant and equipment	$ 727	$ 409