Net Income Per Share - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Numerator:
Net income attributable to Innoviva stockholders, basic	$ 82,046	$ 265,523	$ 118,191	$ 282,235
Net income attributable to Innoviva stockholders, diluted	$ 84,825	$ 268,698	$ 126,598	$ 291,633
Denominator:
Weighted-average shares used to compute basic net income per share attributable to Innoviva stockholders	64,953	69,731	66,016	69,640
Dilutive effect of options and awards granted under equity incentive plan and employee stock purchase plan	106	128	133	94
Weighted-average shares used to compute diluted net income per share attributable to Innoviva stockholders	86,164	95,830	87,504	95,072
Net income per share attributable to Innoviva stockholders
Basic net income per share	$ 1.26	$ 3.81	$ 1.79	$ 4.05
Diluted net income per share	$ 0.98	$ 2.8	$ 1.45	$ 3.07
2023 Notes
Numerator:
Add: interest expense on 2025 Notes, net of tax effect	$ 0	$ 412	$ 86	$ 2,003
Denominator:
Dilutive effect	0	4,866	250	6,629
2025 Notes
Numerator:
Add: interest expense on 2025 Notes, net of tax effect	$ 1,543	$ 1,769	$ 4,618	$ 3,862
Denominator:
Dilutive effect	11,150	11,150	11,150	11,150
2028 Notes
Numerator:
Add: interest expense on 2025 Notes, net of tax effect	$ 1,236	$ 994	$ 3,703	$ 3,533
Denominator:
Dilutive effect	9,955	9,955	9,955	7,559