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 investments in debt securities which are categorized as held-to-maturity and that have scheduled maturities more than one year from the balance sheet date or operating cycle, if longer; such investments are normally measured at amortized cost (carrying value) unless circumstances indicate that the value to be recovered from the investment is less than its carried amount. The held-to-maturity category is for those securities that the Company has the positive intent and ability to hold until maturity.

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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 Trading Securities which consist of all investments in certain debt and equity securities that are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time) or for which an entity has elected the fair value option. Trading generally reflects active and frequent buying and selling, and trading securities are generally used with the objective of generating profits on short-term differences in price, but this category of investments may also include items which are not intended to be sold in the near term or for which the fair value option has been elected.

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Fair Value Measurements (Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended					12 Months Ended				12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012 BCD Semiconductor Manufacturing Limited [Member]	Dec. 31, 2012 BCD Semiconductor Manufacturing Limited [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2012 BCD Semiconductor Manufacturing Limited [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2012 BCD Semiconductor Manufacturing Limited [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2013 Trading Securities [Member]	Dec. 31, 2013 Trading Securities [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2013 Trading Securities [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2013 Trading Securities [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2013 Short-term Investments [Member]	Dec. 31, 2013 Short-term Investments [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2013 Short-term Investments [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2013 Short-term Investments [Member] Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Fair Value Disclosure		$ 7,092	$ 7,092			$ 5,634	$ 5,634	$ 0	$ 0
Changes in Fair Value, Gain (Loss)		3,679				235				0
Short-Term Investments, Fair Value Disclosure										$ 22,922	$ 0	$ 22,922	$ 0
Securities Borrowed Setoff Rights Description	During 2013, the Company entered into a net settlement agreement with China Construction Bank (“CCB”) whereby CCB loaned the Company $20 million and the Company in turn invested the same $20 million with CCB. The principal of the $20 million investment is guaranteed by CCB and is collateral for the $20 million loan. The Company believes that the $20 million investment and loan approximate fair value. The net interest income, which is guaranteed by CCB, realized by the investment was immaterial as of December 31, 2013. The investment and the offsetting loan are non-cancelable, will mature in June 2014 and are shown net of each other on the balance sheet as the Company believes the arrangement qualifies for the offsetting provisions in GAAP.