NET INCOME PER SHARE - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Numerator:
Net income attributable to Innoviva stockholders, basic	$ 213,921	$ 265,854	$ 224,402
Net income attributable to Innoviva stockholders, diluted	$ 225,569	$ 270,590	$ 229,119
Denominator:
Weighted-average shares used to compute basic net income per share attributable to Innoviva stockholders	69,644	82,062	101,320
Dilutive effect of options and awards granted under equity incentive plan and employee stock purchase plan	108	59	45
Weighted-average shares used to compute diluted net income per share attributable to Innoviva stockholders	95,248	94,310	113,554
Net income per share attributable to Innoviva stockholders
Basic net income per share	$ 3.07	$ 3.24	$ 2.21
Diluted net income per share	$ 2.37	$ 2.87	$ 2.02
2023 Notes
Numerator:
Add: interest expense on Notes, net of tax effect	$ 2,439	$ 4,736	$ 4,717
Denominator:
Dilutive effect	6,188	12,189	12,189
2025 Notes
Numerator:
Add: interest expense on Notes, net of tax effect	$ 4,583	$ 0	$ 0
Denominator:
Dilutive effect	11,150	0	0
2028 Notes
Numerator:
Add: interest expense on Notes, net of tax effect	$ 4,626	$ 0	$ 0
Denominator:
Dilutive effect	8,158	0	0