Balance Sheet Account Detail Fair Value Measurements (Details) (Fair Value, Measurements, Recurring, USD $)	Sep. 30, 2014	Dec. 31, 2013
Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	$ 77,100,000	$ 84,900,000
Corporate debt securities | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	27,537,000	95,152,000
Contingently issuable common stock	0	0
Corporate debt securities | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Contingently issuable common stock	0	0
Corporate debt securities | Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Contingently issuable common stock	14,300,000	60,900,000
Corporate debt securities | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	27,537,000	95,152,000
Contingently issuable common stock	$ 14,300,000	$ 60,900,000