Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (1,626)	$ (20,553)
Adjustments to reconcile loss to net cash (used in) provided by operating activities:
Depreciation and amortization	150	146
Amortization (accretion) of investments	649	(151)
Stock-based compensation	13,925	10,591
Amortization of debt discount and debt issuance costs		289
Amortization of intangible asset	361	360
Changes in assets and liabilities:
Accounts receivable, net	3,299	(41,858)
Inventory	(42,028)	(15,352)
Prepaid and other current assets	1,251	(7,416)
Other long-term assets	(24)
Interest receivable	118	(1,021)
Accrued interest payable		(111)
Deferred revenue	(662)	961
Accounts payable and other current liabilities	6,479	79,285
Other long-term liabilities	(596)	(1,033)
Net cash (used in) provided by operating activities	(18,704)	4,137
CASH FLOWS FROM INVESTING ACTIVITIES:
Sale and maturities of securities	127,925	17,077
Purchases of securities		(310,648)
Disposal of furniture, fixtures and equipment	4
Purchases of furniture, fixtures and equipment		(251)
Net cash provided by (used in) investing activities	127,929	(293,822)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options, net of transaction costs	2,059	1,306
Payment on debt from royalty-bearing instrument		(13,330)
Taxes paid related to stock-based awards	(7,252)	(13,831)
Net cash used in financing activities	(5,193)	(25,855)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS AND RESTRICTED CASH	104,032	(315,540)
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING OF PERIOD	190,879	648,495
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH, END OF PERIOD	294,911	332,955
Cash paid during the year for:
Interest		$ 875
Income taxes	5
Supplemental disclosure of non-cash transactions:
Laxdale Milestone	$ 12,000