Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net Income (Loss)	$ (9,333,000)	$ 526,000	$ (19,065,000)	$ (6,108,000)
Other comprehensive income, net of tax:
Unrealized gain on short-term investments, net of tax	3,000	0	21,000	0
Comprehensive Net Income (Loss)	$ (9,330,000)	$ 526,000	$ (19,044,000)	$ (6,108,000)