Consolidated Statements of Operations - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Consolidated Statements of Operations      
Revenue $ 8,378 $ 1,604 $ 148
Costs and operating expenses:      
Cost of revenue 16,523 5,624 667
Research and development 42,806 22,063 16,039
Selling and marketing 22,479 8,669 2,431
General and administrative 16,047 12,600 5,764
Total costs and operating expenses 97,855 48,956 24,901
Loss from operations (89,477) (47,352) (24,753)
Other income (expense), net (94) (79) (26)
Interest expense (211) (61) (59)
Net loss (89,782) (47,492) (24,838)
Net loss attributable to common stockholders $ (89,782) $ (47,492) $ (24,989)
Net loss per share attributable to common stockholders, basic and diluted $ (3.18) $ (56.14) $ (36.13)
Shares used in computing net loss per share attributable to common stockholders, basic and diluted 28,213,324 846,027 691,731