Commitments and Contingencies (Textual) (Details) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended	24 Months Ended
	Apr. 30, 2016 USD ($)	Jun. 30, 2016 USD ($) ft² building	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) ft² building	Jun. 30, 2015 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2015 USD ($)
Commitments and Contingencies [Line Items]
Incentive from lessor		$ 1.5		$ 1.5
Asset retirement obligations		0.4		0.4				$ 0.4
Letters of credit		0.7		0.7				$ 0.7
Rent expense		0.8	$ 0.9	1.7	$ 1.7
Operating lease, sublease rentals		0.3	$ 0.2	0.5	$ 0.3
Operating lease, future minimum sublease rentals		$ 2.3		$ 2.3
Purchase commitment	$ 1.8
Fifth Amendment [Member]
Commitments and Contingencies [Line Items]
Payments for capital improvements						$ 3.6
Tenant reimbursements							$ 3.1
Headquarters, Redwood City [Member] | Fifth Amendment [Member]
Commitments and Contingencies [Line Items]
Lease area space occupancy (square feet) | ft²		107,200		107,200
Number of buildings leased | building		4		4
Chesapeake Space [Member]
Commitments and Contingencies [Line Items]
Expiration date of lease				Jan. 31, 2017
Penobscot Space, Building 2 Space, and Saginaw Space [Member] | Fifth Amendment [Member]
Commitments and Contingencies [Line Items]
Expiration date of lease				Jan. 31, 2020