Stockholders' Equity - Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2017	Apr. 03, 2014
Class of Stock [Line Items]
Shares of common stock reserved for future issuance (in shares)	14,764,000
2014 Equity Incentive Plan
Class of Stock [Line Items]
Shares of common stock reserved for future issuance (in shares)	7,300,000
Employee Stock Options
Class of Stock [Line Items]
Shares of common stock reserved for future issuance (in shares)	4,047,000
Restricted Stock Units
Class of Stock [Line Items]
Shares of common stock reserved for future issuance (in shares)	2,033,000
ESPP
Class of Stock [Line Items]
Shares of common stock reserved for future issuance (in shares)	1,371,000	880,000
Common stock warrants
Class of Stock [Line Items]
Shares of common stock reserved for future issuance (in shares)	13,000