Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Decrease in carrying value of IPR&D due to foreign currency translation	$ 0.5	$ 0.2

Decrease in process research And development due to foreign currency translation.

No definition available.

Name:	svra_DecreaseInProcessResearchAndDevelopmentDueToForeignCurrencyTranslation
Namespace Prefix:	svra_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration