Fair Value Measurements (Proposed) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 M	Dec. 31, 2012 Recurring basis Estimated fair value	Dec. 31, 2011 Recurring basis Estimated fair value	Dec. 31, 2012 Recurring basis Estimated fair value Money Market Funds	Dec. 31, 2011 Recurring basis Estimated fair value Money Market Funds	Dec. 31, 2012 Recurring basis Estimated fair value US government debt securities	Dec. 31, 2011 Recurring basis Estimated fair value US government debt securities	Dec. 31, 2012 Recurring basis Estimated fair value Corporate debt securities	Dec. 31, 2011 Recurring basis Estimated fair value Corporate debt securities	Dec. 31, 2012 Recurring basis Estimated fair value Foreign government debt securities	Dec. 31, 2011 Recurring basis Estimated fair value Foreign government debt securities	Dec. 31, 2012 Recurring basis Quoted Prices in Active Markets for Identical Assets (Level 1) Money Market Funds	Dec. 31, 2011 Recurring basis Quoted Prices in Active Markets for Identical Assets (Level 1) Money Market Funds	Dec. 31, 2012 Recurring basis Quoted Prices in Active Markets for Identical Assets (Level 1) US government debt securities	Dec. 31, 2011 Recurring basis Quoted Prices in Active Markets for Identical Assets (Level 1) US government debt securities	Dec. 31, 2012 Recurring basis Significant Other Observable Inputs (Level 2)	Dec. 31, 2011 Recurring basis Significant Other Observable Inputs (Level 2)	Dec. 31, 2012 Recurring basis Significant Other Observable Inputs (Level 2) US government debt securities	Dec. 31, 2012 Recurring basis Significant Other Observable Inputs (Level 2) Corporate debt securities	Dec. 31, 2011 Recurring basis Significant Other Observable Inputs (Level 2) Corporate debt securities	Dec. 31, 2012 Recurring basis Significant Other Observable Inputs (Level 2) Foreign government debt securities	Dec. 31, 2011 Recurring basis Significant Other Observable Inputs (Level 2) Foreign government debt securities
Fair Value Measurements
Maturity period of cash equivalents to classify as money market funds, maximum (in months)	3
Financial Assets:
Cash and cash equivalents				$ 47,086	$ 40,197							$ 47,086	$ 40,197
Investment, at fair value						59,815	11,323	110,508	52,605					55,817	11,323			3,998	110,508	52,605
Cash and cash equivalents, and short-term investments										2,421	8,432										2,421	8,432
Financial Liabilities:
Debt		$ 95,000	$ 50,000													$ 95,000	$ 50,000