Condensed Consolidated Statements of Income (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Net sales	$ 69,809	$ 71,228	$ 199,169	$ 178,826
Cost of sales	46,639	43,904	132,599	110,165
Gross profit	23,170	27,324	66,570	68,661
Operating expenses:
Research and development	6,525	5,900	20,096	16,788
Selling, general and administrative	9,120	8,121	27,099	24,297
Total operating expenses	15,645	14,021	47,195	41,085
Operating income	7,525	13,303	19,375	27,576
Interest and other income, net	409	585	989	1,156
Gain on sale of investments	0	2,561	560	2,761
Equity in net income of affiliate	251	0	269	0
Income before income taxes	8,185	16,449	21,193	31,493
Provision for income taxes	90	272	126	963
Consolidated net income	8,095	16,177	21,067	30,530
Net loss (income) attributable to noncontrolling interests	(5)	(136)	16	(139)
Net income attributable to ISSI	$ 8,090	$ 16,041	$ 21,083	$ 30,391
Basic net income per share	$ 0.30	$ 0.62	$ 0.79	$ 1.20
Shares used in basic per share calculation	26,768	25,965	26,546	25,429
Diluted net income per share	$ 0.28	$ 0.57	$ 0.74	$ 1.13
Shares used in diluted per share calculation	28,551	28,026	28,322	26,807