Fair Value Measurements

12 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Abstract]

Fair Value Measurements

Note 3. Fair Value Measurements

The following table presents the balances of assets measured at fair value on a recurring basis, by level within the fair value hierarchy, as of the dates presented (in thousands):

	December 31, 2022						December 31, 2021
	Level 1		Level 2		Total		Level 1		Level 2		Total
Cash equivalents:
Money market funds	$	14,620	$	—	$	14,620	$	113,058	$	—	$	113,058
Total cash equivalents		14,620		—		14,620		113,058		—		113,058
Short-term investments:
U.S. government agency securities		—		78,621		78,621		—		4,066		4,066
Corporate notes and bonds		—		26,953		26,953		—		36,966		36,966
Commercial paper		—		24,073		24,073		—		16,489		16,489
Treasury bill		—		11,359		11,359		—		4,490		4,490
Yankee bonds		—		1,939		1,939		—		—		—
Agency bonds		—		2,882		2,882		—		—		—
Asset-backed securities		—		8,321		8,321		—		7,432		7,432
Total short-term investments		—		154,148		154,148		—		69,443		69,443
Long-term investments:
U.S. government agency securities		—		13,462		13,462		—		14,225		14,225
Yankee bonds		—		1,869		1,869		—		—		—
Agency bonds		—		2,983		2,983		—		—		—
Asset-backed securities		—		886		886		—		—		—
Total long-term investments		—		19,200		19,200		—		14,225		14,225
Total	$	14,620	$	173,348	$	187,968	$	113,058	$	83,668	$	196,726

We did not have any Level 3 assets as of December 31, 2022 or 2021. We did not have any liabilities measured at fair value as of December 31, 2022 or 2021. We expect short-term investments to mature within 1 year of the reporting date. We expect long-term investments to mature between 1 and 2 years from the reporting date. See Note 7 for the carrying amount and estimated fair value of our convertible senior notes due 2027.

The following tables present the cost or amortized cost, gross unrealized gains, gross unrealized losses and total estimated fair value of our financial assets as of the dates presented (in thousands):

	December 31, 2022
	Cost or		Gross		Gross			Total Estimated
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Description:
Money market funds	$	14,620	$	—	$	—		$	14,620
U.S. government agency securities		93,065		—		(982	)		92,083
Corporate notes and bonds		27,133		6		(186	)		26,953
Yankee bonds		3,815		—		(7	)		3,808
Commercial paper		24,073		—		—			24,073
Treasury bill		11,361		2		(4	)		11,359
Agency bond		5,863		4		(2	)		5,865
Asset-backed securities		9,287		2		(82	)		9,207
Total	$	189,217	$	14	$	(1,263	)	$	187,968

	December 31, 2021
	Cost or		Gross		Gross			Total Estimated
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Description:
Money market funds	$	113,058	$	—	$	—		$	113,058
U.S. government agency securities		18,314		—		(23	)		18,291
Corporate notes and bonds		36,975		3		(12	)		36,966
Commercial paper		16,489		—		—			16,489
Treasury bill		4,494		—		(4	)		4,490
Asset-backed securities		7,435		—		(3	)		7,432
Total	$	196,765	$	3	$	(42	)	$	196,726

Marketable securities in a continuous loss position for less than 12 months had an estimated fair value of $125.6 million and unrealized losses of $1.2 million as of December 31, 2022. Marketable securities in a continuous loss position for less than 12 months had an estimated fair value of $61.0 million and unrealized losses of $42,000 as of December 31, 2021. Marketable securities in a continuous loss position for greater than 12 months had an estimated fair value of $13.9 million and unrealized losses of $0.1 million as of December 31, 2022. As of December 31, 2021, there were no marketable securities in a continuous loss position for greater than 12 months.

Unrealized losses from our fixed-income securities are primarily attributable to changes in interest rates and not to lower credit ratings of the issuers. In determining whether an unrealized loss is other-than-temporary, for the periods presented, we determined we do not have plans to sell the securities nor is it more likely than not that we would be required to sell the securities before their anticipated recovery.