Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (91,036)	$ (55,158)	$ (213,349)	$ (160,399)
Other comprehensive income:
Unrealized gain (loss) on available-for-sale securities, net of tax	(49)	111	194	259
Comprehensive loss	(91,085)	(55,047)	(213,155)	(160,140)
Comprehensive income attributable to noncontrolling interest (SRX Cardio)	(1,853)		(1,853)
Total comprehensive loss attributable to Portola	$ (92,938)	$ (55,047)	$ (215,008)	$ (160,140)