Fair Value Measurements
We determine the fair values of our financial instruments based on the fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The fair value assumes that the transaction to sell the asset or transfer the liability occurs in the principal or most advantageous market for the asset or liability and establishes that the fair value of an asset or liability shall be determined based on the assumptions that market participants would use in pricing the asset or liability. The classification of a financial asset or liability within the hierarchy is based upon the lowest level input that is significant to the fair value measurement. The fair value hierarchy prioritizes the inputs into three levels that may be used to measure fair value:
Level 1 - Inputs are unadjusted quoted prices in active markets for identical assets or liabilities.
Level 2 - Inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument.
Level 3 - Inputs are unobservable inputs based on our assumptions.
Financial Assets
Cash equivalents primarily consist of AAA-rated money market funds with overnight liquidity and no stated maturities. We classified cash equivalents as Level 1 due to the short-term nature of these instruments and measured the fair value based on quoted prices in active markets for identical assets.
When available, our marketable securities are valued using quoted prices for identical instruments in active markets. If we are unable to value our marketable securities using quoted prices for identical instruments in active markets, we value our investments using broker reports that utilize quoted market prices for comparable instruments. As of December 31, 2025 and 2024, all of our marketable securities were valued using quoted prices for comparable instruments in active markets and are classified as Level 2.
Based on our valuation of our money market funds and marketable securities, we concluded that they are classified in either Level 1 or Level 2. The following table presents information about our assets that are measured at fair value on a recurring basis using the above input categories (in thousands):
Fair Value Measurements as of December 31, 2025Fair Value Measurements as of December 31, 2024
DescriptionTotalLevel 1Level 2TotalLevel 1Level 2
Money market funds$201,592 $201,592 $— $137,201 $137,201 $— 
Commercial paper3,433 — 3,433 2,059 — 2,059 
U.S. treasury debt securities288,619 — 288,619 263,227 — 263,227 
U.S. government agency debt securities78,980 — 78,980 81,022 — 81,022 
Corporate debt securities197,294 — 197,294 178,852 — 178,852 
$769,918 $201,592 $568,326 $662,361 $137,201 $525,160 
Included in cash and cash equivalents$217,066 $147,776 
Included in marketable securities$552,852 $514,585 
Convertible Senior Notes
As of December 31, 2025, the fair value of our convertible senior notes due in 2026 and 2028 was $85.2 million and $691.8 million, respectively. The fair value was determined based on the quoted price of the convertible senior notes in an over-the-counter market on the last trading day of the reporting period and has been classified as Level 2 in the fair value hierarchy. See Note 8 to the consolidated financial statements for more information.

Historical Timeline

Fiscal YearFiled
2025Feb 19, 2026Showing above
2024Feb 25, 2025
2023Feb 20, 2024
2022Feb 21, 2023
2021Feb 22, 2022
2020Feb 17, 2021
2019Feb 20, 2020
2018Feb 20, 2019
2017Feb 22, 2018
2016Feb 23, 2017
2015Mar 1, 2016

About Fair Value Disclosures

Fair value disclosures classify all assets and liabilities measured at fair value into a three-level hierarchy: Level 1 (quoted market prices), Level 2 (observable inputs like yield curves), and Level 3 (unobservable inputs requiring management estimates). The proportion of Level 3 assets directly reflects how much of the balance sheet depends on internal models rather than market evidence.

Key signals: a growing Level 3 balance relative to total fair-value assets increases valuation uncertainty and earnings volatility risk. Watch for transfers between levels — assets moving from Level 2 to Level 3 often signal deteriorating market liquidity. Unrealized gains and losses on Level 3 positions flow through earnings or other comprehensive income, so large swings deserve scrutiny. For financial institutions, examine the sensitivity disclosures that show how Level 3 valuations change under alternative assumptions. Compare the fair value of debt against its carrying amount to gauge hidden leverage.