Investments - Schedule of Cash Equivalents, and Short term Investments (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Total, Amortized Cost	$ 1,509,680		$ 726,061
Total, Gross Unrealized Gains	1,280		845
Total, Gross Unrealized Losses	(145)		(1,352)
Total Fair Value	1,510,815		725,554
Proceeds from sale of cash equivalent investments	20,400	$ 18,100
Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Amortized Cost	609,622		509,067
Short-term investments, Gross Unrealized Gains	1,280		841
Short-term investments, Gross Unrealized Losses	(145)		(1,352)
Short-term investments, Total Fair Value	610,757		508,556
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Amortized Cost	69,830		63,256
Short-term investments, Gross Unrealized Gains	176		168
Short-term investments, Gross Unrealized Losses	(11)		(1,038)
Short-term investments, Total Fair Value	69,995		62,386
Certificate of deposits
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Amortized Cost	17,359		15,121
Short-term investments, Gross Unrealized Gains	0		0
Short-term investments, Gross Unrealized Losses	0		0
Short-term investments, Total Fair Value	17,359		15,121
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Amortized Cost	43,429		36,829
Short-term investments, Gross Unrealized Gains	0		0
Short-term investments, Gross Unrealized Losses	0		0
Short-term investments, Total Fair Value	43,429		36,829
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Amortized Cost	335,150		258,191
Short-term investments, Gross Unrealized Gains	850		567
Short-term investments, Gross Unrealized Losses	(59)		(101)
Short-term investments, Total Fair Value	335,941		258,657
Foreign government bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Amortized Cost	3,074		1,590
Short-term investments, Gross Unrealized Gains	0		0
Short-term investments, Gross Unrealized Losses	(1)		0
Short-term investments, Total Fair Value	3,073		1,590
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Amortized Cost	913		11,159
Short-term investments, Gross Unrealized Gains	2		2
Short-term investments, Gross Unrealized Losses	0		(18)
Short-term investments, Total Fair Value	915		11,143
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Amortized Cost	1,017		1,007
Short-term investments, Gross Unrealized Gains	5		2
Short-term investments, Gross Unrealized Losses	0		0
Short-term investments, Total Fair Value	1,022		1,009
U.S. government agency bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Amortized Cost	7,138		11,392
Short-term investments, Gross Unrealized Gains	0		0
Short-term investments, Gross Unrealized Losses	(4)		(25)
Short-term investments, Total Fair Value	7,134		11,367
U.S. government bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Amortized Cost	131,712		110,522
Short-term investments, Gross Unrealized Gains	247		102
Short-term investments, Gross Unrealized Losses	(70)		(170)
Short-term investments, Total Fair Value	131,889		110,454
Cash equivalents
Debt Securities, Available-for-sale [Line Items]
Cash equivalents, Amortized Cost	900,058		216,994
Cash equivalents, Gross Unrealized Gains	0		4
Cash equivalents, Gross Unrealized Losses	0		0
Cash equivalent, Total Fair Value	900,058		216,998
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Cash equivalents, Amortized Cost	104,623		53,110
Cash equivalents, Gross Unrealized Gains	0		0
Cash equivalents, Gross Unrealized Losses	0		0
Cash equivalent, Total Fair Value	104,623		53,110
Money market funds
Debt Securities, Available-for-sale [Line Items]
Cash equivalents, Amortized Cost	781,489		146,679
Cash equivalents, Gross Unrealized Gains	0		0
Cash equivalents, Gross Unrealized Losses	0		0
Cash equivalent, Total Fair Value	781,489		146,679
U.S. government bonds
Debt Securities, Available-for-sale [Line Items]
Cash equivalents, Amortized Cost	13,946		16,450
Cash equivalents, Gross Unrealized Gains	0		4
Cash equivalents, Gross Unrealized Losses	0		0
Cash equivalent, Total Fair Value	13,946		16,454
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Cash equivalents, Amortized Cost			755
Cash equivalents, Gross Unrealized Gains			0
Cash equivalents, Gross Unrealized Losses			0
Cash equivalent, Total Fair Value			755
Level 1
Debt Securities, Available-for-sale [Line Items]
Total Fair Value	944,683		288,708
Level 1 \| Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	149,248		125,575
Level 1 \| Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	0		0
Level 1 \| Certificate of deposits
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	17,359		15,121
Level 1 \| Commercial paper
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	0		0
Level 1 \| Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	0		0
Level 1 \| Foreign government bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	0		0
Level 1 \| Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	0		0
Level 1 \| Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	0		0
Level 1 \| U.S. government agency bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	0		0
Level 1 \| U.S. government bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	131,889		110,454
Level 1 \| Cash equivalents
Debt Securities, Available-for-sale [Line Items]
Cash equivalent, Total Fair Value	795,435		163,133
Level 1 \| Commercial paper
Debt Securities, Available-for-sale [Line Items]
Cash equivalent, Total Fair Value	0		0
Level 1 \| Money market funds
Debt Securities, Available-for-sale [Line Items]
Cash equivalent, Total Fair Value	781,489		146,679
Level 1 \| U.S. government bonds
Debt Securities, Available-for-sale [Line Items]
Cash equivalent, Total Fair Value	13,946		16,454
Level 1 \| Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Cash equivalent, Total Fair Value			0
Level 2
Debt Securities, Available-for-sale [Line Items]
Total Fair Value	566,132		436,846
Level 2 \| Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	461,509		382,981
Level 2 \| Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	69,995		62,386
Level 2 \| Certificate of deposits
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	0		0
Level 2 \| Commercial paper
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	43,429		36,829
Level 2 \| Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	335,941		258,657
Level 2 \| Foreign government bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	3,073		1,590
Level 2 \| Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	915		11,143
Level 2 \| Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	1,022		1,009
Level 2 \| U.S. government agency bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	7,134		11,367
Level 2 \| U.S. government bonds
Debt Securities, Available-for-sale [Line Items]
Short-term investments, Total Fair Value	0		0
Level 2 \| Cash equivalents
Debt Securities, Available-for-sale [Line Items]
Cash equivalent, Total Fair Value	104,623		53,865
Level 2 \| Commercial paper
Debt Securities, Available-for-sale [Line Items]
Cash equivalent, Total Fair Value	104,623		53,110
Level 2 \| Money market funds
Debt Securities, Available-for-sale [Line Items]
Cash equivalent, Total Fair Value	0		0
Level 2 \| U.S. government bonds
Debt Securities, Available-for-sale [Line Items]
Cash equivalent, Total Fair Value	$ 0		0
Level 2 \| Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Cash equivalent, Total Fair Value			$ 755

AMKOR TECHNOLOGY, INC. 10-Q