The bill was initially spearheaded by Sen. Robert Marshall (Dem), who wanted to create the Community Firearm Recovery Program. The program has allocated $200,000 tax dollars to the project for the next fiscal year. This is in addition to the $100,000 that the program has already spent towards purchasing privately owned civilian firearms.
Marshall hoped to extend the program, which is slated to expire July 1. Evidently, the fact that the Delaware Senate had already put aside enough money in its budget for the upcoming year was not enough to tempt the senators into voting for SB 204 again. Sen. Dave Lawson (Rep) lead those opposed to the bill by acquiring a 13-9 vote to end SB 204, freeing up the $200,000 for other purposes.
You can find a full list of who voted for what here. Republican senators voted roughly along party lines, with only one republican voting for the bill. The democrats were split approximately 50-50 on the issue.