Provided herein are formulations, processes, solid forms and methods of use relating to the compound of formula (I):having the name 1-ethyl-7-(2-methyl-6-(1H-1,2,4-triazol-3-yl)pyridin-3-yl)-3,4-dihydropyrazino[2,3-b]pyrazin-2(1H)-one and tautomers thereof.