Equity Award Plan Activities - Shares Available for Grant (Details) shares in Thousands	6 Months Ended
	Jun. 30, 2016 shares
Shares Available for Grant [Roll Forward]
Shares available for grant beginning balance (in shares)	10,495
Authorized (in shares)	2,044
Options granted (in shares)	(440)
Options canceled (in shares)	232
Options repurchased (in shares)	5
Shares traded for taxes	9
Shares available for grant ending balance (in shares)	12,032
Restricted Stock Units (RSUs)
Shares Available for Grant [Roll Forward]
RSUs granted (in shares)	(369)
RSUs forfeited (in shares)	56