Stockholders' Equity (Details) - Convertible preferred stock - USD ($) $ in Thousands	Mar. 31, 2018	Feb. 13, 2018	Dec. 31, 2017
Stockholders' Equity (Details) - Convertible preferred stock [Line Items]
Preferred stock, shares authorized	5,000,000		5,000,000
Preferred stock, shares outstanding	0		1,221,064
Preferred stock, net carrying value			$ 1
Preferred stock, liquidation preference	$ 39,956		$ 39,956
Convertible Preferred Stock [Member]
Stockholders' Equity (Details) - Convertible preferred stock [Line Items]
Preferred stock, shares authorized			1,662,171
Preferred stock, shares outstanding			1,221,064
Preferred stock, net carrying value			$ 38,941
Preferred stock, liquidation preference			$ 39,956
Convertible Preferred Stock [Member] | Series A Preferred Stock [Member]
Stockholders' Equity (Details) - Convertible preferred stock [Line Items]
Preferred stock, shares authorized			94,988
Preferred stock, shares outstanding			94,988
Preferred stock, net carrying value			$ 2,949
Preferred stock, liquidation preference			$ 2,737
Convertible Preferred Stock [Member] | Series B Preferred Stock [Member]
Stockholders' Equity (Details) - Convertible preferred stock [Line Items]
Preferred stock, shares authorized			747,095
Preferred stock, shares outstanding		483,387	520,973
Preferred stock, net carrying value			$ 16,115
Preferred stock, liquidation preference			$ 17,219
Convertible Preferred Stock [Member] | Series C Preferred Stock [Member]
Stockholders' Equity (Details) - Convertible preferred stock [Line Items]
Preferred stock, shares authorized			820,088
Preferred stock, shares outstanding			605,103
Preferred stock, net carrying value			$ 19,877
Preferred stock, liquidation preference			$ 20,000