Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Collaboration and license revenue	$ 35,504,000	$ 12,070,000	$ 9,625,000
Operating expenses:
Research and development	246,854,000	200,376,000	123,639,000
Selling, general and administrative	58,235,000	38,869,000	23,552,000
Total operating expenses	305,089,000	239,245,000	147,191,000
Loss from operations	(269,585,000)	(227,175,000)	(137,566,000)
Interest and other income, net	1,472,000	305,000	441,000
Loss before taxes	(268,113,000)	(226,870,000)	(137,125,000)
Income tax benefit	0	365,000
Net loss	(268,113,000)	(226,505,000)	(137,125,000)
Net income attributable to noncontrolling interest (SRX Cardio)	(930,000)
Net loss attributable to Portola	$ (269,043,000)	$ (226,505,000)	$ (137,125,000)
Net loss per share attributable to Portola common stockholders:
Basic and diluted	$ (4.76)	$ (4.36)	$ (3.19)
Shares used to compute net loss per share attributable to Portola common stockholders:
Basic and diluted	56,480,647	51,981,463	42,977,463