v3.26.3
Fair Value Measurements - Schedule of Cost, Gross Unrealized Losses, Gross Unrealized Gains, and Fair Values Company’s Investments (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Short-term Investments $ 245,043 $ 224,088
Long-term Investments 150,392 134,376
Fair Value, Inputs, Level 1, Level 2, and Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cost 2,224,275 1,289,990
Gross Unrealized Holding Loss (1,731) (12)
Gross Unrealized Holding Gain 28 809
Fair Value 2,222,572 1,290,787
Cash and Cash Equivalents 1,805,427 946,932
Short-term Investments 245,043 222,088
Long-term Investments 134,962 121,767
Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cost 1,920,174 1,023,748
Gross Unrealized Holding Loss (362) 0
Gross Unrealized Holding Gain 0 204
Fair Value 1,919,812 1,023,952
Cash and Cash Equivalents 1,805,427 946,932
Short-term Investments 50,108 52,002
Long-term Investments 27,137 25,018
Level 1 | Money market funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cost 1,842,567 946,932
Gross Unrealized Holding Loss 0 0
Gross Unrealized Holding Gain 0 0
Fair Value 1,842,567 946,932
Cash and Cash Equivalents 1,805,427 946,932
Short-term Investments 0 0
Long-term Investments 0 0
Level 1 | Money market funds | Location, Statement of Financial Position, Balance [Axis]: etsy:FundsReceivableAndSellerAccountsCurrent    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value 37,100  
Level 1 | U.S. Government securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cost 77,607 76,816
Gross Unrealized Holding Loss (362) 0
Gross Unrealized Holding Gain 0 204
Fair Value 77,245 77,020
Cash and Cash Equivalents 0 0
Short-term Investments 50,108 52,002
Long-term Investments 27,137 25,018
Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cost 286,601 253,242
Gross Unrealized Holding Loss (1,369) (12)
Gross Unrealized Holding Gain 28 605
Fair Value 285,260 253,835
Cash and Cash Equivalents 0 0
Short-term Investments 190,935 170,086
Long-term Investments 94,325 83,749
Level 2 | Certificate of deposit    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cost 11,279 20,913
Gross Unrealized Holding Loss (11) 0
Gross Unrealized Holding Gain 1 30
Fair Value 11,269 20,943
Cash and Cash Equivalents 0 0
Short-term Investments 11,269 19,240
Long-term Investments 0 1,703
Level 2 | Commercial paper    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cost 63,394 32,409
Gross Unrealized Holding Loss (105) 0
Gross Unrealized Holding Gain 0 26
Fair Value 63,289 32,435
Cash and Cash Equivalents 0 0
Short-term Investments 63,289 32,435
Long-term Investments 0 0
Level 2 | Corporate bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cost 211,928 199,920
Gross Unrealized Holding Loss (1,253) (12)
Gross Unrealized Holding Gain 27 549
Fair Value 210,702 200,457
Cash and Cash Equivalents 0 0
Short-term Investments 116,377 118,411
Long-term Investments 94,325 82,046
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cost 17,500 13,000
Gross Unrealized Holding Loss 0 0
Gross Unrealized Holding Gain 0 0
Fair Value 17,500 13,000
Cash and Cash Equivalents 0 0
Short-term Investments 4,000 0
Long-term Investments 13,500 13,000
Level 3 | Loans receivable - held for investment    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cost 17,500 13,000
Gross Unrealized Holding Loss 0 0
Gross Unrealized Holding Gain 0 0
Fair Value 17,500 13,000
Cash and Cash Equivalents 0 0
Short-term Investments 4,000 0
Long-term Investments 13,500 13,000
Measured at NAV | Third-party managed funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Short-term Investments   2,000
Long-term Investments $ 15,430 $ 12,609