REDWOOD CITY, Calif.--(BUSINESS WIRE)--Silver Spring Networks, Inc. (NYSE: SSNI) today announced financial results for its fourth quarter and year ended December 31, 2014. Fourth Quarter Results (all comparisons made are against the prior year period) Non-GAAP revenue for the fourth quarter was $70.4 million, down 22%. GAAP revenue was $77.4 million, down 20%. Non-GAAP gross margin was 41.3%, as compared with 30.0% a year ago. GAAP gross margin was 39.0% as compared with 34.7% a year ago. Non-G