Tesla has delayed the launch date for the Model X crossover yet again, with the first deliveries now expected in the third quarter of next year.

The Palo Alto, Calif.-based automaker is still testing the highly anticipated Model X, which is expected to compete with models including the Infiniti QX60 Hybrid, Lexus RX 450h and Porsche Macan, according to Edmunds.com.

"Work continues on the finalization of Model X with the testing of Alpha prototypes and initial builds of the first Beta prototypes," Tesla said in a shareholder letter. "Model X powertrain development is almost complete with the early introduction of Dual Motor drive on Model S. We recently decided to build in significantly more validation testing time to achieve the best Model X possible."

Deliveries for the Model X should start in the third quarter of 2015, a few months later than the crossover was recently slated to launch. Initially, the Model X and its "falcon-wing" doors were expected in early 2014, Edmunds reported.

Earlier this year, Tesla CEO Elon Musk cited his "perfectionist" nature as one reason why the model isn't quite ready for production.

"It's damn hard to make an SUV in particular that is beautiful and yet incredibly functional at the same time," Musk told Bloomberg in February. "It's a harder design problem than the Model S."

Tesla expects to spend about $350 million in the fourth quarter of this year to go toward increased production capacity, construction of the much-touted Nevada battery plant and global expansion.

The electric carmaker is putting long-term goals over short-term profit, forgoing revenue rather than offering a subpar product to consumers, said the letter.  

"There are many other companies that do not follow this philosophy that may be a more attractive home for investor capital," the automaker told shareholders. "Tesla is not going to change."

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