Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2013

Fair Value of Assets and Liabilities Measured on Recurring Basis

The following tables summarize the basis used to measure certain financial assets and liabilities at fair value on a recurring basis in the condensed consolidated balance sheets:

Balance at December 31, 2013 (in thousands)	Total		Quoted Prices in Active Markets for Identical Items (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Common stock warrant liability	$	15,071	$	—	$	—	$	15,071