Commitments and Contingencies (Textual) (Details) $ in Thousands		1 Months Ended			3 Months Ended		9 Months Ended		12 Months Ended	24 Months Ended
	Aug. 11, 2016 claim	Oct. 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Sep. 30, 2012	Sep. 30, 2016 USD ($) ft² building	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) ft² building	Sep. 30, 2015 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2015 USD ($)
Commitments and Contingencies [Line Items]
Incentive from lessor					$ 1,400		$ 1,400
Asset retirement obligations					400		400				$ 400
Noncurrent restricted cash					783		783				$ 787
Rent expense					900	$ 900	2,600	$ 2,600
Operating lease, sublease rentals					300	$ 200	900	$ 500
Operating lease, future minimum sublease rentals					$ 2,100		$ 2,100
Claims dismissed | claim	5
Purchase Commitment [Member]
Commitments and Contingencies [Line Items]
Purchase commitment			$ 1,800
Fifth Amendment [Member]
Commitments and Contingencies [Line Items]
Payments for capital improvements									$ 3,600
Tenant reimbursements										$ 3,100
Sixth Amendment [Member]
Commitments and Contingencies [Line Items]
Area of land | ft²					11,020		11,020
Operating leases, renewal term				2 years
Operating leases, term of contract				5 years
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
Minimum [Member]
Commitments and Contingencies [Line Items]
Expiration date of lease							Jan. 31, 2017
Maximum [Member]
Commitments and Contingencies [Line Items]
Expiration date of lease							Jan. 31, 2020
Subsequent Event [Member]
Commitments and Contingencies [Line Items]
Purchase commitment		$ 1,400
Subsequent Event [Member] | Seventh Amendment [Member]
Commitments and Contingencies [Line Items]
Expiration date of lease		Jan. 31, 2022
Operating leases, term of contract		5 years