Stockholders' Equity (Deficit) - Common Stock - Additional Information (Details)	12 Months Ended
Dec. 31, 2018 Class
Class Of Stock [Line Items]
Number of classes	2
Class A Common Stock
Class Of Stock [Line Items]
Common stock, voting right	one vote for each share
Class B Common Stock
Class Of Stock [Line Items]
Common stock, voting right	ten votes for each share

Description of voting rights of common stock. Includes eligibility to vote and votes per share owned. Include also, if any, unusual voting rights.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

Name:	us-gaap_CommonStockVotingRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration