Netflix's new show "Stranger Things" is a massive hit, charming critics, viewers, and Wall Street analysts alike.

But it wasn't always clear that it was going to be a success, according to its creators, Matt and Ross Duffer.

The show, a supernatural thriller filled with '80s nostalgia, wasn't a concept that networks immediately "got." In fact, Matt told Rolling Stone that "Stranger Things" had been rejected 15 to 20 times by different networks.

The executives particularly didn't like that "Stranger Things" was a show with children as lead actors but wasn't intended for kids.

"There was a week where we were like, 'This isn't going to work because people don't get it,'" Matt told Rolling Stone.

But that was before Netflix.

The Duffers' story lends credence to the theory that Netflix has a knack for identifying which seemingly niche shows will have massive appeal.

Pacific Crest analysts Andy Hargreaves and Evan Wingren pointed to this in a note to investors on Tuesday.

"Netflix has taken an idea and a project that was off the radar of most, and grown an audience at what is likely a small fraction of the cost per hour viewed of any other TV show to premiere this year," they wrote.

The analysts think this is evidence that Netflix's big original-content push is destined for success.

Netflix will release a whopping 600 hours of original content this year. The question isn't whether it can identify a sleeper hit like "Stranger Things" or "Making a Murderer," but whether it can be more cost-effective on the whole at producing hits that drive subscriber growth.

Note: "Stranger Things" executive producer Shawn Levy told Variety that Netflix was the first buyer they pitched after he became involved with the show.