Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (226,505)	$ (137,125)	$ (83,352)
Other comprehensive income:
Unrealized gain on available-for-sale securities, net of tax	89	(294)	22
Comprehensive loss	226,416	137,419	83,330
Total comprehensive loss attributable to Portola	$ (226,416)	$ (137,419)	$ (83,330)