Four months and a business lifetime ago, critics were poking holes in the newfound success of videoconferencing upstart Zoom Video Communications. Its safety wasn’t up to snuff, its product was engineered in China, and too many of its newest customers weren’t paying.

This latter group was of particular concern. Virtual bar mitzvah celebrations, surprisingly delightful Zoomtails with distant friends, and rapid adoption by schools catapulted Zoom into the zeitgeist. But non-business uses sucked up Zoom’s server capacity without generating much revenue. As Michal Lev-Ram wrote in Fortune in April: “Zoom may have become a beloved household name even as it faces unexpected scrutiny for its less-than-perfect security. But its success when the world returns to normal is anything but assured.”

The good news for Zoom is that the world hasn’t returned to normal. Its gross margins indeed have been walloped by all the spending to support a rapidly growing business. Adjusted gross margins dropped 10 percentage points from the year before, according to the company’s quarterly earnings released on August 31. Yet because Zoom is growing its base of revenue-paying customers too, and making so much money in the process, the hit to margins feels practically meaningless.

Zoom says the percentage of revenue attributed to customers with 10 or fewer employees jumped to 36%, from 30%. Quarterly revenue hit $664 million, a fivefold jump from the year before. It generated $373 million in free cash flow. The year-ago figure was just $17 million.

Zoom already was a modestly hot company when the year began, the result of a product popular with businesses and a successful IPO. With the pandemic, it is on fire, and whatever its challenges are, they seem minor. In pre-market trading September 1 morning, its stock is now well above 10 times the $36 IPO price from April last year. And if any company can claim that even in a post-pandemic world its product will remain relevant, Zoom is it.