Two people who were on the call, one says they were concerned about the details discussed and reported it, the other stated they weren't concerned. Neither are attorneys, however the one who was "not concerned that anything illegal was discussed." also corroborated the other's testimony about tying military aid to investigations benefiting the Trump re-elect. Democrats have to prove corruption, quid pro quo and/or campaign finance regulations sufficient enough to garner enough votes in the Senate to remove the President from office and that's the key.
Without a doubt, the House will pass formal articles of impeachment and on the flip-side, the Senate will not vote to ratify the impeachment at the two-thirds majority level.