The 3760 needs 1.2mA nominal to turn on. I reckon a cheap old 6N138/6N139 (0.5mA threshold) would server you better, even if you only get half-wave from it. They have a minimum gain of about 4, typical gain of 11. Or an HCPL-2731 has a typical gain of 35 at 0.5mA!
You won't be driving the neon (directly) from the output of one of these; a neon needs a lot more voltage. LEDs, sure.