Just a reminder from the Mika Q & A portion of the Investor's Conference in early April:

[23:55] Does the company expect to secure additional development projects that will continue to contribute NRE revenue during 2020...

"Absolutely yes we do expect additional NRE revenue during 2020. And all of that is going to be related to actual product sales in 2021."

If I'm reading the quote correctly, there is Non Recurring Engineering which will be tied to actual sales of the Optical Interposer (hopefully on a large scale) which depending on the model, should mean additional revenue.