Shares of Lululemon tumbled 17 percent after hours Wednesday, as investors overlooked the company's fiscal fourth-quarter sales and earnings growth and focused on its slow start to 2017.

The athletic wear maker expects to earn between 25 cents and 27 cents a share during the quarter, well below Wall Street's consensus forecast of 39 cents a share, according to Thomson Reuters.

Lululemon's sales outlook also fell short of analysts' expectations, due to a slowdown in store traffic and fewer online shoppers making purchases. Lululemon expects to ring up between $510 million and $515 million in fiscal first-quarter revenue, compared with Wall Street's expectation of $552.3 million.

Analysts were more focused on Lululemon's outlook than its fourth-quarter results, which it had already preannounced.

"We own it, and by owning it we also mean that we know how to fix it," CEO Laurent Potdevin told investors on the company's earnings call.