コンソールで起動してみたら
$ /path/to/IntelliJ/Contents/MacOS/idea
2019-07-31 18:58:10.483 idea[1064:19215] allVms required 1.8*,1.8+
2019-07-31 18:58:10.487 idea[1064:19219] Value of IDEA_VM_OPTIONS is (null)
2019-07-31 18:58:10.487 idea[1064:19219] Processing VMOptions file at /Users/Leo.K/Library/Preferences/IntelliJIdea2019.2/idea.vmoptions
2019-07-31 18:58:10.487 idea[1064:19219] Done
OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.
Error occurred during initialization of VM
Initial heap size set to a larger value than the maximum heap size
/Users/Leo.K/Library/Preferences/IntelliJIdea2019.2/idea.vmoptionsファイル削除
$ mv /Users/Leo.K/Library/Preferences/IntelliJIdea2019.2/idea.vmoptions /tmp/