Stockholders' Equity and Stock Repurchase Program (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	$ 145,546,000
Stock-based compensation	292,000
Net (loss) income	(1,835,000)	(1,959,000)
Dividends declared by joint ventures	(83,000)
Change in unrealized (loss) gain on marketable securities	(10,000)	(17,000)
Currency translation adjustment	(521,000)
Balance, end of period	143,389,000		145,546,000
Stock repurchase program, authorized amount	6,000,000
Shares repurchased (in shares)	0		285,000
Average price of shares repurchased (in dollars per share)			$ 2.51
Total purchase price			716,000
Amount available for future repurchases			5,300,000
Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, end of period	3,532,000		3,532,000
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, end of period	32,000		32,000
Additional Paid In Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	194,156,000
Stock-based compensation	292,000
Balance, end of period	194,448,000
Accumulated Deficit [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	(67,005,000)
Net (loss) income	(2,040,000)
Balance, end of period	(69,045,000)
Other Comprehensive Income/(loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	8,953,000
Change in unrealized (loss) gain on marketable securities	(10,000)
Currency translation adjustment	(442,000)
Balance, end of period	8,501,000
AXT, Inc. stockholders equity [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	139,668,000
Stock-based compensation	292,000
Net (loss) income	(2,040,000)
Change in unrealized (loss) gain on marketable securities	(10,000)
Currency translation adjustment	(442,000)
Balance, end of period	137,468,000
Noncontrolling interests [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	5,878,000
Net (loss) income	205,000
Dividends declared by joint ventures	(83,000)
Currency translation adjustment	(79,000)
Balance, end of period	$ 5,921,000