Business InsiderFitbit shares dropped by as much as 15% in after-hours trading Monday after the company reported quarterly results. Profits and revenues for the fourth quarter crushed estimates, but guidance for the current quarter was weak. In the earnings release, Fitbit said higher manufacturing costs, and the global launch of new products — the Fitbit Blaze and Alta — would impact its first-quarter results. Fitbit said it expects Q1 revenues to be in a range of $420 to $440 million, below the expectation for $484.6 million according to Bloomberg.