Organization and Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Summary of Financial Instruments Measured at Fair Value on Recurring Basis

The following tables summarize the Company’s financial instruments measured at fair value on a recurring basis (in thousands):

			Fair Value Measurements at Reporting Date Using
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
As of June 30, 2023:
Assets:
Cash equivalents:
Money market funds	$	29,431	$	29,431	$	—	$	—
Total cash equivalents		29,431		29,431		—		—
Short-term investments:
U.S. Treasury securities		27,099		27,099		—		—
U.S. agency bonds		104,150		—		104,150		—
U.S. agency discount notes		4,424		—		4,424		—
Asset-backed securities		4,921		—		4,921		—
Corporate debt securities		1,978		—		1,978		—
Commercial paper		127,014		—		127,014		—
Total short-term investments		269,586		27,099		242,487		—
Restricted cash:
Money market account		816		816		—		—
Total restricted cash		816		816		—		—
Total assets measured at fair value on a recurring basis	$	299,833	$	57,346	$	242,487	$	—

			Fair Value Measurements at Reporting Date Using
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
As of December 31, 2022:
Assets:
Cash equivalents:
Money market funds	$	12,697	$	12,697	$	—	$	—
Total cash equivalents		12,697		12,697		—		—
Short-term investments:
U.S. Treasury securities		63,016		63,016		—		—
U.S. agency bonds		67,020		—		67,020		—
U.S. agency discount notes		4,334		—		4,334		—
Corporate debt securities		1,970		—		1,970		—
Commercial paper		139,250		—		139,250		—
Total short-term investments		275,590		63,016		212,574		—
Restricted cash:
Money market account		816		816		—		—
Total restricted cash		816		816		—		—
Total assets measured at fair value on a recurring basis	$	289,103	$	76,529	$	212,574	$	—

Reconciliation of Cash and Cash Equivalents and Restricted Cash

The following table provides a reconciliation of cash and cash equivalents and restricted cash reported within the accompanying balance sheets that sum to the amounts shown in the statements of cash flows (in thousands):

	June 30, 2023		December 31, 2022
Cash and cash equivalents	$	33,703	$	51,426
Restricted cash		816		816
Total cash and cash equivalents and restricted cash	$	34,519	$	52,242

Summary of Short-Term Investments

The following tables summarize short-term investments (in thousands):

	As of June 30, 2023
	Amortized		Unrealized					Estimated
	Cost		Gains		Losses			Fair Value
U.S. Treasury securities	$	27,172	$	—	$	(73	)	$	27,099
U.S. agency bonds		104,875		—		(725	)		104,150
U.S. agency discount notes		4,427		—		(3	)		4,424
Asset-backed securities		4,974		—		(53	)		4,921
Corporate debt securities		1,987		—		(9	)		1,978
Commercial paper		127,211		3		(200	)		127,014
Total	$	270,646	$	3	$	(1,063	)	$	269,586

	As of December 31, 2022
	Amortized		Unrealized					Estimated
	Cost		Gains		Losses			Fair Value
U.S. Treasury securities	$	63,675	$	—	$	(659	)	$	63,016
U.S. agency bonds		67,421		—		(401	)		67,020
U.S. agency discount notes		4,321		13		—			4,334
Corporate debt securities		1,975		—		(5	)		1,970
Commercial paper		139,733		26		(509	)		139,250
Total	$	277,125	$	39	$	(1,574	)	$	275,590

The amortized cost and estimated fair value in the tables above exclude $1.5 million and $0.7 million of accrued interest receivable as of June 30, 2023 and December 31, 2022, respectively. Accrued interest receivable is included in prepaid expenses and other current assets in the accompanying balance sheets.

Schedule of Contractual Maturities of Available-for-sale Debt Securities

Contractual maturities of available-for-sale debt securities are as follows (in thousands):

	As of June 30, 2023
	Due in 1 Year or Less		Due Between 1 and 2 Years
U.S. Treasury securities	$	5,736	$	21,363
U.S. agency bonds		58,647		45,503
U.S. agency discount notes		4,424		—
Asset-backed securities		—		4,921
Corporate debt securities		1,978		—
Commercial paper		127,014		—
Total	$	197,799	$	71,787

	As of December 31, 2022
	Due in 1 Year or Less		Due Between 1 and 2 Years
U.S. Treasury securities	$	57,369	$	5,647
U.S. agency bonds		37,202		29,818
U.S. agency discount notes		4,334		—
Corporate debt securities		—		1,970
Commercial paper		139,250		—
Total	$	238,155	$	37,435

Schedule of Available-for-Sale Debt Securities in an Unrealized Loss Position

The following table summarizes our available-for-sale debt securities in an unrealized loss position for which an allowance for credit losses has not been recorded, aggregated by major security type and length of time in a continuous unrealized loss position (in thousands):

	As of June 30, 2023
	Less Than 12 Months					12 Months or Longer					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. Treasury securities	$	27,099	$	(73	)	$	—	$	—		$	27,099	$	(73	)
U.S. agency bonds		99,155		(720	)		4,995		(5	)		104,150		(725	)
U.S. agency discount notes		4,424		(3	)		—		—			4,424		(3	)
Asset-backed securities		4,921		(53	)		—		—			4,921		(53	)
Corporate debt securities		1,978		(9	)		—		—			1,978		(9	)
Commercial paper		99,633		(200	)		—		—			99,633		(200	)
Total	$	237,210	$	(1,058	)	$	4,995	$	(5	)	$	242,205	$	(1,063	)

	As of December 31, 2022
	Less Than 12 Months					12 Months or Longer					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. Treasury securities	$	15,566	$	(82	)	$	47,450	$	(577	)	$	63,016	$	(659	)
U.S. agency bonds		67,020		(401	)		—		—			67,020		(401	)
Corporate debt securities		1,970		(5	)		—		—			1,970		(5	)
Commercial paper		118,840		(509	)		—		—			118,840		(509	)
Total	$	203,396	$	(997	)	$	47,450	$	(577	)	$	250,846	$	(1,574	)

Summary of Potentially Dilutive Shares Not Included in the Calculation of Net Loss Per Share

Potentially dilutive securities not included in the calculation of diluted net loss per share, because to do so would be anti-dilutive, are as follows (in common stock equivalent shares):

	June 30,
	2023		2022
Common stock options		9,076,276		7,548,970
Unvested common stock		23,690		161,760
Employee stock purchase plan shares		8,276		5,936
Total potentially dilutive shares		9,108,242		7,716,666