Commitments and Contingencies (Textual) (Details) (USD $)	3 Months Ended		12 Months Ended	24 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2014
Commitments and Contingencies [Line Items]
Incentive from Lessor	$ 1,600,000
Asset retirement obligations					300,000
Asset Retirement Obligation, Accretion Expense		0
Operating Leases, Rent Expense	800,000	800,000
Sublease income	200,000	0
Estimated obligation payable	600,000
Fifth Amendment [Member]
Commitments and Contingencies [Line Items]
Payments for Capital Improvements			3,600,000
Tenant Reimbursements				3,100,000
Sixth Amendment [Member]
Commitments and Contingencies [Line Items]
Letters of credit	$ 700,000				$ 700,000
Headquarters, Redwood City [Member] | Fifth Amendment [Member]
Commitments and Contingencies [Line Items]
Lease area space occupancy (square feet)	107,000
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