CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (45,027,000)	$ (27,939,000)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation expense	10,346,000	4,761,000
Depreciation and amortization	4,413,000	4,279,000
Noncash operating lease cost	1,732,000	1,048,000
Amortization of premium on short-term investments	1,554,000	63,000
Other	111,000
Changes in operating assets and liabilities
Accounts receivable	(4,184,000)	(2,603,000)
Inventory and other deferred costs	117,000	(1,662,000)
Prepaid expenses and other assets	(3,542,000)	(2,065,000)
Accounts payable	(3,530,000)	(1,628,000)
Accrued and other current liabilities	1,839,000	1,174,000
Contract liabilities	(18,067,000)	(15,383,000)
Operating lease liabilities	(952,000)	(637,000)
Other long-term liabilities	(364,000)	471,000
Net cash used in operating activities	(55,554,000)	(40,121,000)
Cash flows from investing activities:
Purchases of available-for-sale debt securities	(227,316,000)	(80,104,000)
Proceeds from maturities of available-for-sale debt securities	129,783,000	80,510,000
Proceeds from sales of available-for-sale debt securities	5,059,000
Purchases of property and equipment	(7,506,000)	(2,409,000)
Net cash used in investing activities	(99,980,000)	(2,003,000)
Cash flows from financing activities:
Proceeds from public offerings, net of underwriting discounts and commissions	162,258,000	117,500,000
Payments of costs related to public offerings	(342,000)	(93,000)
Proceeds from loans	5,167,000
Repayments of loans	(1,857,000)
Proceeds from exercise of equity awards	3,127,000	2,920,000
Net cash provided by financing activities	168,353,000	120,327,000
Effect of exchange rates on cash, cash equivalents and restricted cash	18,000	(4,000)
Net change in cash, cash equivalents and restricted cash	12,837,000	78,199,000
Cash and cash equivalents, beginning of period	68,525,000	55,046,000
Cash, cash equivalents and restricted cash, end of period	81,362,000	133,245,000
Reconciliation of cash, cash equivalents and restricted cash to the condensed consolidated balance sheets:
Cash and cash equivalents	79,572,000	133,245,000
Restricted cash, included in other long-term assets	1,790,000
Total cash, cash equivalents and restricted cash	$ 81,362,000	$ 133,245,000