Per Share Data (Calculation of Basic and Diluted EPS) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended														12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Numerator for basic and diluted net income (loss) per share:
Net income (loss)	$ 2,832	$ 6,186	[1]	$ 8,812	[2]	$ 5,435	[3]	$ 4,698	[4]	$ 7,064	[5]	$ 3,287	[6]	$ 2,499	$ 23,265	$ 17,548	$ (2,718)
Denominator for basic net income (loss) per share:
Weighted average common shares outstanding															30,037	28,223	27,120
Dilutive effect of stock options and awards (shares)															1,586	1,471	0
Denominator for diluted net income (loss) per share (shares)															31,623	29,694	27,120
Basic net income (loss) per share	$ 0.09	$ 0.20		$ 0.30		$ 0.19		$ 0.16		$ 0.25		$ 0.12		$ 0.09	$ 0.77	$ 0.62	$ (0.10)
Diluted net income (loss) per share	$ 0.09	$ 0.19		$ 0.28		$ 0.18		$ 0.15		$ 0.24		$ 0.11		$ 0.09	$ 0.74	$ 0.59	$ (0.10)

[1] In the June 2014 quarter, the Company realized a gain of $2.1 million from the sale of its remaining freely-tradeable shares of Nanya common stock.

[2] In the March 2014 quarter, the Company realized a gain from the sale of investments of $6.0 million including $3.9 million from the sale of a portion of its shares of Nanya common stock and $2.1 million from the sale of its remaining shares of SMIC common stock.

[3] In the December 2013 quarter, the Company realized a gain of $3.1 million from the sale of a portion of its shares of Nanya common stock.

[4] In the September 2013 quarter, the Company realized a gain of $2.9 million from the sale of a portion of its shares of Nanya common stock.

[5] In the June 2013 quarter, the Company realized a gain from the sale of investments of $7.3 million including $7.0 million from the sale of a portion of its shares of Nanya common stock.

[6] In the March 2013 quarter, the Company realized a gain of $2.1 million from the sale of a portion of its shares of Nanya common stock.