Phosphatase that hydrolyzes imidodiphosphate, 3-phosphohistidine and 6-phospholysine. Has broad substrate specificity and can also hydrolyze inorganic diphosphate, but with lower efficiency (By similarity). diphosphate + H2O = H(+) + 2 phosphate Binds 1 Mg(2+) ion per subunit. Optimum pH is 7.0 for PNP, and 5.5 for PPi. Homodimer. Expressed in brain, and at lower levels in liver and kidney. Detected in thyroid (at protein level). Expressed in liver, kidney and moderately in brain. Belongs to the HAD-like hydrolase superfamily.