Financial Instruments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Transfers of assets between fair value hierarchy levels	$ 0	$ 0
Fair Value Measurements, Recurring | Level 1 | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents consisting of money market funds	38,700,000	$ 15,300,000
Fair Value Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of assets	0
Fair value liabilities	0
Fair Value Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of assets	0
Fair value liabilities	$ 0