Energy Conversion Devices Inc. finally proved itself. A cousin of sorts to solar energy phenom First Solar Inc., the firm conspicuously sat out last year’s stunning rally in the sector’s shares.

But today was the day for earnings show and tell, and the believers were vindicated. Solar sales rose 193% from the period a year earlier, and the company posted a profit of 17 cents a share. Analysts, on average, had expected break-even. The result: ENER stock soared $15.10 to $49.91, or 43%, for Nasdaq’s biggest gain.

Energy Conversion fashions solar modules based on “thin film” silicon that can be designed into roofs for big-box stores, airplane hangars and other commercial buildings. With the financial success of First Solar, investors have taken a shine to the thin-film concept.

FSLR, however, uses cadmium telluride to convert the sun’s rays into electric power. Both formulas bypass the supply bottleneck and price inflation that bedevil makers of conventional, slab-style silicon solar cells, and that’s key. Part of Energy Conversion’s secret is also the lightness and flexibility of its wares, making them a convenient and cost-effective feature in construction.

With its history rooted in R&D, the company has struggled to get its act together as an efficient manufacturer and sales machine. Now, tributes are being paid to the new chief executive, Mark Morelli, for making the operation jell.

Energy Conversion’s target market is also jelling, and in the quarter that just ended, the company was firing on all cylinders. Instead of their usual gradual slide, selling prices were firm. Gross margin tells the tale. It blossomed from 19.2% to 30.7% in just one quarter. Analysts had expected an improvement to about 25%.