Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Details) - shares shares in Thousands	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Common stock reserved for future issuance (shares)	9,646	5,745
Shares subject to outstanding warrants to purchase common stock
Class of Stock [Line Items]
Common stock reserved for future issuance (shares)	28	28
Stock options and RSUs outstanding
Class of Stock [Line Items]
Common stock reserved for future issuance (shares)	4,692	4,033
Available for future grants under employee equity plans
Class of Stock [Line Items]
Common stock reserved for future issuance (shares)	4,926	1,684