Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net Loss Attributable to Common Stockholders	$ (9,732,000)	$ (6,634,000)
Other comprehensive income, net of tax:
Unrealized gain on short-term investments, net of tax	18,000	0
Comprehensive Net Loss	$ (9,714,000)	$ (6,634,000)