Basis of Presentation (Details)		1 Months Ended									3 Months Ended			9 Months Ended	12 Months Ended
	Jan. 25, 2021 USD ($)	Aug. 31, 2022 USD ($)	Jul. 31, 2022 USD ($)	May 31, 2022 USD ($)	Apr. 30, 2022 USD ($)	Jan. 31, 2022 USD ($)	Jun. 30, 2021 USD ($)	May 31, 2021 USD ($)	Feb. 28, 2021 USD ($)	Jan. 31, 2021 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Sep. 30, 2022 USD ($) company	Dec. 31, 2021 USD ($) company	Dec. 31, 2020 USD ($)	Oct. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Nov. 30, 2020	May 31, 2019	Apr. 30, 2019
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of equity method investments | company														6	5
Investments, equity method														$ 13,727,000	$ 10,166,000
Investment in subsidiary with noncontrolling interest											$ 1,179,000	$ 575,000	$ 576,000
AXT-Tongmei, Inc | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Cash consideration							$ 1,000,000					$ 1,000,000
Chao Yang XinMei High Purity Semiconductor Materials Co. Ltd. | Loan from related party
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment in subsidiary with noncontrolling interest					$ 4,500,000
Increase in redeemable noncontrolling interests				$ 100,000
Chao Yang XinMei High Purity Semiconductor Materials Co. Ltd. | Loan from related party | ChaoYang Xinshuo
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Loan amount																	$ 1,000,000.0	$ 900,000
Investment in subsidiary with noncontrolling interest					1,900,000
Amount paid to subsidiary				600,000	700,000
Chao Yang XinMei High Purity Semiconductor Materials Co. Ltd. | Loan from related party | Beijing Tongmei Xtal Technology
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment in subsidiary with noncontrolling interest					2,600,000
Amount paid to subsidiary				$ 800,000	$ 1,100,000
Increase in noncontrolling interest						$ 2,200,000
Increase in redeemable noncontrolling interests						$ 200,000
Chao Yang XinMei High Purity Semiconductor Materials Co. Ltd.
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment value, agreement amount								$ 1,800,000	$ 3,000,000.0
Investments, equity method									$ 1,800,000
Ownership (as a percent)			58.50%	58.50%	58.50%	58.50%		58.50%	58.50%
Initial funding								$ 1,500,000	$ 1,500,000
Increase in noncontrolling interest			$ 610,000
Further investment			600,000
Redeemable noncontrolling interest increased			57,000
ChaoYang ShuoMei High Purity Semiconductor Materials Co., Ltd.
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment value, agreement amount					$ 4,400,000
Investments, equity method					$ 3,300,000
Ownership (as a percent)					75.00%
Initial funding		$ 334,000
Increase in noncontrolling interest		406,000
Redeemable noncontrolling interest increased		73,000
ChaoYang KaiMei Quartz Co., Ltd
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment value, agreement amount					$ 7,600,000
Investments, equity method					$ 3,000,000.0									$ 843,000
Ownership (as a percent)					40.00%									40.00%
Initial funding			2,200,000
Investment amount			900,000
Beijing BoYu Semiconductor Vessel Craftwork Technology Co., Ltd Investment
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Percentage of outstanding shares																33.00%
Percentage of ownership																67.00%			63.00%
Beijing Tongmei Xtal Technology
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Percentage of outstanding shares	7.28%													14.50%
Private equity ownership percentage	7.28%													14.50%
Percentage of key managers and contributors purchased																0.40%
Investment in new facility	$ 49,000,000															$ 48,100,000
Raised additional capital										$ 1,500,000
Percentage of ownership							85.50%					85.50%
Transaction results in increase to noncontrolling interests							$ 1,200,000
Transaction results in increase to redeemable noncontrolling interests							$ 1,200,000
Increase in redeemable noncontrolling interests										$ 1,500,000						$ 48,100,000
Beijing Tongmei Xtal Technology | Beijing Boyu Semiconductor Vessel Craftwork Technology Co Ltd
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Private equity ownership percentage																7.59%
Beijing Tongmei Xtal Technology | Nanjing JinMei Gallium Co., Ltd
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Private equity ownership percentage																0.38%
Beijing Tongmei Xtal Technology | Chao Yang XinMei High Purity Semiconductor Materials Co. Ltd.
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Loan amount						$ 1,400,000									$ 1,400,000
Beijing Tongmei Xtal Technology | Chao Yang XinMei High Purity Semiconductor Materials Co. Ltd. | Loan from related party
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Increase in noncontrolling interest				$ 1,400,000
Beijing Tongmei Xtal Technology | Chao Yang XinMei High Purity Semiconductor Materials Co. Ltd.
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment amount								$ 900,000	$ 900,000
Further investment			800,000
Nanjing JinMei Gallium Co., Ltd Investment
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Percentage of outstanding shares																8.50%
Percentage of ownership																				100.00%	97.00%
Nanjing JinMei Gallium Co., Ltd Investment | Nanjing JinMei Gallium Co., Ltd
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Private equity ownership percentage																0.38%
Chao Yang XinMei High Purity Semiconductor Materials Co. Ltd. | ChaoYang ShuoMei High Purity Semiconductor Materials Co., Ltd.
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Initial funding		$ 1,000,000.0	$ 1,000,000.0