Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenues, net of returns and allowances	$ 29,453	$ 73,611
Cost of sales	20,328	53,274
Gross profit	9,125	20,337
Selling, general and administrative	8,221	10,580
Research, development and engineering	1,946	1,991
Restructuring charges	874	0
Operating (loss) income	(1,916)	7,766
Loss from equity method investment	0	(26)
Interest income (expense) and other income, net	144	(48)
(Loss) Income before income taxes	(1,772)	7,692
Income tax provision	600	1,240
Net (loss) income	$ (2,372)	$ 6,452
(Loss) Income Per Share:
Basic (loss) income per share attributable to Amtech shareholders (USD per share)	$ (0.17)	$ 0.44
Weighted average shares outstanding - basic (in shares)	14,220	14,781
Diluted (loss) income per share attributable to Amtech shareholders (USD per share)	$ (0.17)	$ 0.42
Weighted average shares outstanding - diluted (in shares)	14,220	15,298