Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities:
Net loss	$ (220,683,000)	$ (227,278,000)	$ (204,749,000)
Adjustments to reconcile net loss to net cash used for operating activities:
Stock-based compensation expense	46,851,000	50,218,000	51,411,000
Depreciation and amortization	3,021,000	2,847,000	2,044,000
Amortization of debt discount	785,000	1,429,000	1,050,000
Amortization of debt issuance costs	119,000
Amortization of premium (accretion of discount) on short-term investments	332,000	125,000	(3,730,000)
Realized gain on available-for-sale investments	0	0	(8,000)
Impairment of property and equipment	478,000	847,000	107,000
Loss on disposal of property and equipment	822,000		62,000
Change in operating assets and liabilities:
Accounts receivable	6,351,000	(1,971,000)	24,773,000
Inventory	(6,477,000)	(16,937,000)	14,064,000
Prepaid expenses and other assets	(8,386,000)	1,295,000	(12,052,000)
Accounts payable	3,278,000	(2,233,000)	(14,105,000)
Accrued clinical and manufacturing liabilities	(26,246,000)	15,348,000	10,144,000
Accrued payroll and employee liabilities	1,666,000	(1,651,000)	1,851,000
Other accrued liabilities	(5,265,000)	(6,859,000)	4,558,000
Net cash used for operating activities	(203,354,000)	(184,820,000)	(124,580,000)
Investing activities:
Purchases of short-term investments	(129,221,000)	(134,007,000)	(477,035,000)
Maturities and sales of short-term investments	164,940,000	349,775,000	462,406,000
Purchases of property and equipment	(3,022,000)	(6,813,000)	(7,154,000)
Proceeds from the sale of property and equipment	32,000
Net cash provided by (used for) investing activities	32,729,000	208,955,000	(21,783,000)
Financing activities:
Net proceeds from sale of common stock			162,151,000
Net proceeds from convertible notes financing	148,963,000
Proceeds from purchases under the Employee Stock Purchase Plan	2,139,000	2,317,000	2,109,000
Proceeds from stock issued under the equity incentive plan	4,926,000	6,759,000	22,164,000
Proceeds from conversion of convertible notes payable		26,000
Proceeds from warrant exercises		3,000	1,000
Net cash provided by financing activities	156,028,000	9,105,000	186,425,000
Net increase (decrease) in cash and cash equivalents	(14,597,000)	33,240,000	40,062,000
Cash and cash equivalents at beginning of year	105,138,000	71,898,000	31,836,000
Cash and cash equivalents at end of year	90,541,000	$ 105,138,000	$ 71,898,000
Supplemental disclosure of cash flow information:
Interest paid	$ 1,244,000