Net Income per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Numerator [Abstract]
Net income (loss) attributable to AXT, Inc	$ (1,228)	$ (2,295)	$ (2,035)	$ (2,400)	$ (756)	$ 932	$ 1,299	$ 1,635	$ (7,958)	$ 3,110	$ 20,320
Less: Preferred stock dividends									(177)	(177)	(177)
Net income (loss) to common stockholders									$ (8,135)	$ 2,933	$ 20,143
Denominator [Abstract]
Weighted average common shares (basic)									32,700	32,144	31,872
Effect of Dilutive Securities on Earnings Per Share [Line Items]
Weighted average common shares (dilutive)									32,700	32,865	33,061
Basic net income (loss) per share [Abstract]
Net income attributable to AXT, Inc (in dollars per share)									$ (0.25)	$ 0.10	$ 0.64
Net income to common stockholders (in dollars per share)	$ (0.04)	$ (0.07)	$ (0.06)	$ (0.08)	$ (0.02)	$ 0.03	$ 0.04	$ 0.05	$ (0.25)	$ 0.09	$ 0.63
Diluted net income (loss) per share [Abstract]
Net income attributable to AXT, Inc (in dollars per share)									$ (0.25)	$ 0.09	$ 0.61
Net income to common stockholders (in dollars per share)	$ (0.04)	$ (0.07)	$ (0.06)	$ (0.08)	$ (0.02)	$ 0.03	$ 0.04	$ 0.05	$ (0.25)	$ 0.09	$ 0.61
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from diluted net income per share as the impact is anti-dilutive (in shares)									241	13	116
Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from diluted net income per share as the impact is anti-dilutive (in shares)									2,671	1,056	478
Common stock options [Member]
Effect of Dilutive Securities on Earnings Per Share [Line Items]
Effect of dilutive securities (in shares)									0	689	1,093
Restricted stock [Member]
Effect of Dilutive Securities on Earnings Per Share [Line Items]
Effect of dilutive securities (in shares)									0	32	96