Commitments and Contingencies (Textual) (Details) $ in Thousands			1 Months Ended			3 Months Ended		12 Months Ended	24 Months Ended
	Mar. 31, 2017 USD ($) ft² building	Aug. 11, 2016 claim	Feb. 28, 2017 USD ($)	Oct. 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Mar. 31, 2017 USD ($) ft² building	Mar. 31, 2016 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2016 USD ($)
Commitments and Contingencies [Line Items]
Incentive from lessor	$ 1,200					$ 1,200
Asset retirement obligations	400					400				$ 400
Noncurrent restricted cash	1,592					1,592				1,624
Rent expense						900	$ 900
Capital lease obligations incurred			$ 400
Capital leases, term of contract			3 years
Operating lease, sublease rentals						300	$ 200
Operating lease, future minimum sublease rentals	$ 2,000					$ 2,000
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
Headquarters, Redwood City [Member] | Sixth 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, 2020
Maximum [Member]
Commitments and Contingencies [Line Items]
Expiration date of lease						Jan. 31, 2022
Standby Letters of Credit [Member]
Commitments and Contingencies [Line Items]
Noncurrent restricted cash	$ 700					$ 700				$ 800
Research and Development Arrangement [Member]
Commitments and Contingencies [Line Items]
Purchase commitment	$ 200			$ 1,400
Manufacturing costs						$ 1,200