Equity Award Plan Activities - Shares Available for Grant (Details) shares in Thousands	3 Months Ended
	Mar. 31, 2017 shares
Shares Available for Grant [Roll Forward]
Shares available for grant beginning balance (in shares)	11,754
Authorized (in shares)	2,124
Options granted (in shares)	(165)
Options canceled (in shares)	223
Options repurchased (in shares)	2
Shares traded for taxes (in shares)	5
Shares available for grant ending balance (in shares)	13,680
Restricted Stock Units (RSUs)
Shares Available for Grant [Roll Forward]
RSUs granted (in shares)	(283)
RSUs forfeited (in shares)	20