Tada - This is the highest I know of. Since I was looking it up, I might as well give everyone the history as I can find.

April 15, 2009 - NGN $2.72,  1 sh, 0.40 wt

Jan. 28, 2010 - $2.50,  1 sh, 0.25 wt

June 3, 2010 - $3.30, 1 sh, 0.40 wt

June 17, 2010 - $3.23, 1 sh, 0.40 wt

June 2011 - $1.80, could find no mention of wts

Nov. 2011 - $1.18, Eastern Capital, could find no mention of wts

Jan. 2012 - 15mm shares mentioned in lawyer filings supplement to Oct., 2011Base Shelf           Prospectus. Can find no confirmation of exercise so have no price.

Aug., 2013 - Eastern Capital, $0.90, 1 sh, 0.30 wt

June, 2014 - $0.65, no mention of wts. Bought by NGN with about 1 million shares by RVX directors and officers

July 2015 - HL & Eastern, $2.67, 1 sh, 0.075 wt

June 20, 2017 - $1.80, 1 sh, 1 wt. $4.6mm through Bloom Burton, $5.3mm HL & Eastern

Sept. 2017 - $1.50, 1 sh, 0.50 wt

Oct. 2017 - HL, $1.44, 1 sh, 0.083 wt

Aug. 2018 - $2.50, 1 sh, 0.50 wt

Nov. 2018 - $3.00, 1 sh, 0.50 wt

Jan. 2019 - $3.00, 1 sh, 0.50 wt

April 2019 - $3.00, 1 sh, 0.50 wt

May 2019( maybe) - $4.00, 1 sh, 1 wt

I hope I got them all and made no typos!