Aldeyra Therapeutics Inc. and Scynexis Inc. got their initial public offerings (IPO) out the door Friday, but the tiny raise for Aldeyra – nearly half the amount sought in its January filing as Aldexa Therapeutics Inc. – and the brusque greeting for Scynexis shares – off 11 percent from the $10 offering price – suggested May might not put a spring into the step of biotechs entering the public markets.