WiFi startup Zenreach has officially emerged from stealth mode, announcing that it's raised $50 million and added PayPal cofounder and early Facebook investor Peter Thiel to its board.

Zenreach uses WiFi to help merchants find out how many times a customer returns to a store. When customers login to a store's free, customized WiFi with their email addresses, merchants can track how many times customers return.

The company has remained quiet for the last three years, but despite the low profile, Zenreach has grown to a staff of 150 and raised $50 million through three funding rounds -- including a $30 million Series B round led by Founders Fund founder and Facebook board member Peter Thiel, according to a blog post by Zenreach founder Jack Abraham.

Thiel has drawn a lot of attention lately for being a delegate for presidential candidate Donald Trump -- a stand that puts him in opposition to a lot of Silicon Valley -- and for the revelation that he secretly funded a series of lawsuits against media company Gawker. Thiel is slated to speak at the Republican convention ahead of Trump on Thursday night.

Zenreach's other investors include 8 VC, Bain Capital Ventures, First Round Capital, Felicis Ventures, SoftTech VC, and SV Angel. The company plans to use its latest investment to grow to 300 employees and open a new international office in Dublin, according Forbes reporter Alex Konrad.