Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating Activities
Net loss	$ (67,222)	$ (64,357)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	13,158	11,068
Amortization of premium and accretion of discounts on marketable securities, net	1,894	1,987
Depreciation expense	360	232
Non-cash interest expense		399
Loss on extinguishment of debt		212
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(5,199)	(2,166)
Other long-term assets	(5)	(1,178)
Accounts payable and accrued expenses	(5,592)	(2,688)
Other long-term liabilities	84	(100)
Net cash used in operating activities	(62,522)	(56,591)
Investing Activities
Maturities of marketable securities	115,947	129,969
Purchases of marketable securities	(107,579)	(353,088)
Purchases of property and equipment	(233)	(322)
Net cash provided by (used in) investing activities	8,135	(223,441)
Financing Activities
Proceeds from issuance of stock under equity plans	2,972	1,374
Repayment of long-term debt		(7,250)
Payment of fees related to extinguishment of debt		(611)
Net cash provided by (used in) financing activities	2,972	(6,487)
Net decrease in cash, cash equivalents and restricted cash	(51,415)	(286,519)
Cash, cash equivalents and restricted cash at beginning of period	90,882	325,703
Cash, cash equivalents and restricted cash at end of period	$ 39,467	$ 39,184