Merger with Aravive Biologics, Inc - Schedule of Estimate Purchase Price Fair Value Identifiable Tangible and Intangible Assets Acquired and Liabilities Assumed (Parenthetical) (Detail) - Aravive Biologics [Member] - Common Stock [Member]	Oct. 12, 2018 $ / shares shares
Business Acquisition [Line Items]
Common stock, shares issued | shares	5,141,915
Common stock, value per share | $ / shares	$ 7.26