Net Income Per Share - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net income attributable to Innoviva stockholders, basic	$ 34,865	$ 15,773
Net income attributable to Innoviva stockholders, diluted	$ 37,574	$ 18,342
Denominator:
Weighted-average shares used to compute basic net income per share attributable to Innoviva stockholders	67,786	69,544
Dilutive effect of options and awards granted under equity incentive plan and employee stock purchase plan	139	116
Weighted-average shares used to compute diluted net income per share attributable to Innoviva stockholders	89,788	93,730
Net income per share attributable to Innoviva stockholders
Basic net income per share	$ 0.51	$ 0.23
Diluted net income per share	$ 0.42	$ 0.20
2023 Notes
Numerator:
Add: interest expense on 2025 Notes, net of tax effect	$ 81	$ 1,021
Denominator:
Dilutive effect	757	10,155
2025 Notes
Numerator:
Add: interest expense on 2025 Notes, net of tax effect	$ 1,169	$ 1,164
Denominator:
Dilutive effect	11,150	11,150
2028 Notes
Numerator:
Add: interest expense on 2025 Notes, net of tax effect	$ 1,459	$ 384
Denominator:
Dilutive effect	9,956	2,765