Consolidated Statements of Changes in Redeemable Convertible Preferred Stock and Stockholders' (Parenthetical)	12 Months Ended
Dec. 31, 2018
Redeemable Convertible Preferred Stock, Series C, C1, C2, and D
Dividend rate	8.00%

The percentage rate used to calculate dividend payments on preferred stock.

No definition available.

Name:	us-gaap_PreferredStockDividendRatePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration