Balance Sheet Components - Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Prepaid expenses and other current assets, net
Prepaid expenses	$ 9,893	$ 6,170
Other current assets, net	169	296
Total prepaid expenses and other current assets, net	$ 10,062	$ 6,466