Consolidated Financial Statements Detail - Additional Information 3 (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Total proceeds from sale of equipment and disposal of certain equipment		$ 1,614,000
Total carrying value of equipment sold and disposed		400,000
Depreciation expense	$ 30,000	300,000
Other Income [Member]
Property Plant And Equipment [Line Items]
Gain (loss) on sale of equipment		$ 1,200,000