Subsequent Event	9 Months Ended
Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Event	9. Subsequent Event Merger with Aravive Biologics, Inc. On October 12, 2018, pursuant to the terms of the Agreement and Plan of Merger and Reorganization, dated as of June 3, 2018, by and between Versartis, Inc., Velo Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of Versartis (“Merger Sub”), and Aravive Biologics, Merger Sub was merged with and into Aravive Biologics (the “Merger”), with Aravive Biologics surviving the Merger as a wholly-owned subsidiary of Versartis, Inc. Pursuant to the terms of the Merger Agreement, at the Effective Time, each outstanding share of capital stock of Aravive Biologics (other than any shares held as treasury stock) was converted into the right to receive 2.2801 shares of Versartis’ common stock, par value $0.0001 per share (the “Company Common Stock”), without giving effect to any adjustment for the reverse stock split described below, and (b) each outstanding Aravive Biologics stock option, all of which were in-the-money, whether vested or unvested, that had not previously been exercised prior to the Effective Time was converted into an option to purchase 2.2801 shares of the Company Common Stock for each share of Aravive common stock covered by such option. The aggregate consideration issuable in the Merger to the former security holders of Aravive Biologics, without giving effect to any adjustment for the reverse stock split described below, was approximately 30,851,600 shares of Company Common Stock and options to purchase approximately 7,103,859 shares of Company Common Stock. The Merger is expected to be accounted for as an asset acquisition by Versartis, Inc. To determine the accounting for this transaction under GAAP, Versartis, Inc. assessed whether an integrated set of assets and activities were accounted for as an acquisition of a business or an asset acquisition. The guidance requires an initial screen test to determine if substantially all of the fair value of the gross assets acquired is concentrated in a single asset or group of similar assets. If that screen is met, the set is not a business. In connection with the acquisition of Aravive Biologics, the Company expects substantially all the fair value is included in in-process research and development of Aravive Biologics’ lead asset, AVB-S6-500 and, as such, the acquisition will be treated as an asset acquisition. Management of Versartis, Inc. and Aravive Biologics have made a preliminary estimate of the purchase price of approximately $54.2 million for the fair value of the identifiable tangible and intangible assets acquired and liabilities assumed as of June 30, 2018. The net tangible and intangible assets acquired and liabilities assumed in connection with the transaction will be recorded based on their relative fair values allocation as of October 12, 2018 and the value associated with in-process research and development will be expensed. Corporate Name Change On October 15, 2018, Versartis, Inc. changed its name to “Aravive, Inc.” (“Aravive, Inc.”). Shares of Company Common Stock were previously listed on the Nasdaq Global Select Market under the symbol “VSAR.” Versartis filed with The Nasdaq Stock Market, LLC (“Nasdaq”) a notification form for the listing of additional shares with respect to the shares of Company Common Stock to be issued to the holders of Aravive Biologics capital stock in the Merger so that these shares are listed on Nasdaq. The Company Common Stock began trading on the Nasdaq Global Select Market under the symbol “ARAV” on October 16, 2018. Reverse Stock Split One-for-Six In connection with the completion of the Merger, on October 15, 2018, the amended and restated certificate of incorporation of Versartis was amended to effect, at 12:01 a.m. Eastern Time on October 16, 2018, a reverse split of Company Common Stock at a ratio of 1-for-6 (the “Amended Certificate”). The accompanying financial statements and notes to financial statements give retroactive effect to the reverse stock split for all periods presented. 2479 E. Bayshore Blvd Sublease In October 2018, the Company executed a sublease agreement in Palo Alto, California for approximately 4,240 square feet for office space. The rental term of the sublease commences on October 30, 2018 and expires August 31, 2020. The total obligation for the Company under this lease is approximately $0.3M.

9. Subsequent Event

Merger with Aravive Biologics, Inc.

On October 12, 2018, pursuant to the terms of the Agreement and Plan of Merger and Reorganization, dated as of June 3, 2018, by and between Versartis, Inc., Velo Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of Versartis (“Merger Sub”), and Aravive Biologics, Merger Sub was merged with and into Aravive Biologics (the “Merger”), with Aravive Biologics surviving the Merger as a wholly-owned subsidiary of Versartis, Inc. Pursuant to the terms of the Merger Agreement, at the Effective Time, each outstanding share of capital stock of Aravive Biologics (other than any shares held as treasury stock) was converted into the right to receive 2.2801 shares of Versartis’ common stock, par value $0.0001 per share (the “Company Common Stock”), without giving effect to any adjustment for the reverse stock split described below, and (b) each outstanding Aravive Biologics stock option, all of which were in-the-money, whether vested or unvested, that had not previously been exercised prior to the Effective Time was converted into an option to purchase 2.2801 shares of the Company Common Stock for each share of Aravive common stock covered by such option. The aggregate consideration issuable in the Merger to the former security holders of Aravive Biologics, without giving effect to any adjustment for the reverse stock split described below, was approximately 30,851,600 shares of Company Common Stock and options to purchase approximately 7,103,859 shares of Company Common Stock.

The Merger is expected to be accounted for as an asset acquisition by Versartis, Inc. To determine the accounting for this transaction under GAAP, Versartis, Inc. assessed whether an integrated set of assets and activities were accounted for as an acquisition of a business or an asset acquisition. The guidance requires an initial screen test to determine if substantially all of the fair value of the gross assets acquired is concentrated in a single asset or group of similar assets. If that screen is met, the set is not a business. In connection with the acquisition of Aravive Biologics, the Company expects substantially all the fair value is included in in-process research and development of Aravive Biologics’ lead asset, AVB-S6-500 and, as such, the acquisition will be treated as an asset acquisition. Management of Versartis, Inc. and Aravive Biologics have made a preliminary estimate of the purchase price of approximately $54.2 million for the fair value of the identifiable tangible and intangible assets acquired and liabilities assumed as of June 30, 2018. The net tangible and intangible assets acquired and liabilities assumed in connection with the transaction will be recorded based on their relative fair values allocation as of October 12, 2018 and the value associated with in-process research and development will be expensed.

Corporate Name Change

On October 15, 2018, Versartis, Inc. changed its name to “Aravive, Inc.” (“Aravive, Inc.”). Shares of Company Common Stock were previously listed on the Nasdaq Global Select Market under the symbol “VSAR.” Versartis filed with The Nasdaq Stock Market, LLC (“Nasdaq”) a notification form for the listing of additional shares with respect to the shares of Company Common Stock to be issued to the holders of Aravive Biologics capital stock in the Merger so that these shares are listed on Nasdaq. The Company Common Stock began trading on the Nasdaq Global Select Market under the symbol “ARAV” on October 16, 2018.

Reverse Stock Split One-for-Six

In connection with the completion of the Merger, on October 15, 2018, the amended and restated certificate of incorporation of Versartis was amended to effect, at 12:01 a.m. Eastern Time on October 16, 2018, a reverse split of Company Common Stock at a ratio of 1-for-6 (the “Amended Certificate”). The accompanying financial statements and notes to financial statements give retroactive effect to the reverse stock split for all periods presented.

2479 E. Bayshore Blvd Sublease

In October 2018, the Company executed a sublease agreement in Palo Alto, California for approximately 4,240 square feet for office space. The rental term of the sublease commences on October 30, 2018 and expires August 31, 2020. The total obligation for the Company under this lease is approximately $0.3M.