Stockholders' Equity - Common Stock Reserved For Future Issuance (Details) - shares	Dec. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Number of options outstanding (in shares)	2,582,517	3,027,717
Shares available	13,177,722
RSUs [Member]
Class of Stock [Line Items]
Shares available	6,136,702	5,140,627
Available for future stock option and restricted stock unit grants [Member]
Class of Stock [Line Items]
Shares available	2,131,126
Employee Stock Purchase Plan 2011 [Member] | Available for future employee stock purchase plan options [Member]
Class of Stock [Line Items]
Shares available	2,327,377