SUPPLEMENTARY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended								12 Months Ended
	Jun. 02, 2014	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
SUPPLEMENTARY FINANCIAL DATA (UNAUDITED)
Dividend in ordinary shares distributed to Innoviva's stockholders	32,260,105
Total revenue		$ 5,692	$ 19,075	$ 5,471	$ 18,410	$ 3,893	$ 10,698	$ 7,134	$ 20,401	$ 48,648	$ 42,126	$ 11,688
Costs and expenses		63,526	52,569	52,968	60,052	59,667	53,793	52,427	58,138	229,115	224,025	244,227
Loss from operations		(57,834)	(33,494)	(47,497)	(41,642)	(55,774)	(43,095)	(45,293)	(37,737)	(180,467)	(181,899)	(232,539)
Net loss		$ (67,332)	$ (33,962)	$ (47,225)	$ (42,150)	$ (44,828)	$ (47,314)	$ (47,603)	$ (42,474)	$ (190,669)	$ (182,219)	$ (237,038)
Basic and diluted net loss per share (in dollars per share)		$ (1.36)	$ (0.73)	$ (1.06)	$ (1.10)	$ (1.23)	$ (1.40)	$ (1.42)	$ (1.29)	$ (4.26)	$ (5.34)	$ (7.46)
Reduction in provision for income taxes primary due to changes in transfer pricing						$ 10,800