Fair Value Measurements (Marketable Equity and Cash Equivalents (Classified as Available-for-sale) and Cost Method Investments) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 70,305	$ 49,758
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	(1,835)	(1,929)
Fair Value	68,470	47,829
Money market instruments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	34,317	34,281
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Fair Value	34,317	34,281
Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	18,302	12,051
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Fair Value	18,302	12,051
Available-for-sale securities \| SMIC
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,099	3,426
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	(1,929)
Fair Value	1,099	1,497
Available-for-sale securities \| Nanya
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	16,587
Gross Unrealized Holding Gains	0
Gross Unrealized Holding Losses	(1,835)
Fair Value	14,752
Cash and Cash Equivalents and Restricted Cash
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	47,177	43,068
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Fair Value	47,177	43,068
Short-term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,128	6,690
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	(1,835)	(1,929)
Fair Value	$ 21,293	$ 4,761

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

+ References+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details