Commitments and Contingencies (Narrative) (Details)		1 Months Ended		12 Months Ended
	Dec. 29, 2016 USD ($)	Jan. 31, 2016 USD ($) ft²	Feb. 28, 2015 ft²	Dec. 31, 2016 USD ($) ft²	Dec. 31, 2015 USD ($) ft²	Dec. 31, 2014 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)
Property Subject to or Available for Operating Lease [Line Items]
Office space | ft²					3,713
Approximate total lease payments				$ 983,000
Rent expense				$ 1,093,000	$ 699,000	$ 176,000
Thirty-two Month Sublease Agreement, Expiring October 31, 2017 [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease agreement period			32 months
Area of space, in sqft | ft²			18,599
Lab Space [Member]
Property Subject to or Available for Operating Lease [Line Items]
Area of space, in sqft | ft²		24,105		4,047
Term of lease agreement		20 months
Approximate total lease payments		$ 726,000
4550 Towne Centre Court, San Diego, California [Member]
Property Subject to or Available for Operating Lease [Line Items]
Term of lease agreement	10 years
Term for option to extend lease agreement	5 years
Annual rent under the Lease				$ 3,636,000
4550 Towne Centre Court, San Diego, California [Member] | Letter of Credit
Property Subject to or Available for Operating Lease [Line Items]
Security deposit	$ 303,000
4550 Towne Centre Court, San Diego, California [Member] | Letter of Credit | Scenario, Forecast [Member]
Property Subject to or Available for Operating Lease [Line Items]
Security deposit							$ 303,000	$ 606,000	$ 909,000