These are triumphant times at Apple Inc. But patent litigation over Apple’s best-selling tablet computer, the iPad, could dampen the festive mood.

First, the good news for Apple and its devotees: The company thrived during the final calendar quarter of 2011—the first full quarter since its founder Steve Jobs’s death—posting a staggering $46.3 billion in revenue. As expected, iPhone sales were up 128 percent over the same quarter in 2010, accounting for more than half of Apple’s revenue.