Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes Disclosure [Line Items]
Current tax expense	$ 0	$ 0	$ 0
Deferred tax expense	$ 0	$ 0	$ 0
Tax benefit computed at federal statutory rate	21.00%	21.00%	34.00%
Deferred tax assets decreased due to re-measurement	$ 300,000
Earnings from foreign subsidiaries	0
Income tax provision for deemed repatriation tax	0
Valuation allowance increase (decrease)	(814,000)	$ 1,780,000
Federal [Member]
Income Taxes Disclosure [Line Items]
Net operating loss carryforwards	342,400,000
Net operating loss carryforwards subject to expiration	325,000,000
Net operating loss carryforwards not subject to expiration	3,500,000	$ 8,400,000	$ 17,900,000
State [Member]
Income Taxes Disclosure [Line Items]
Reduction of future taxable income	17,900,000
Incurred Prior to 2016 Ownership Changes [Member]
Income Taxes Disclosure [Line Items]
Annual limitation on ownership changes	71,000
Incurred Subsequent to 2016 Ownership Changes [Member]
Income Taxes Disclosure [Line Items]
Net operating loss carryforwards	5,900,000
Additional losses released from limitation	$ 115,000
Earliest Tax Year [Member]
Income Taxes Disclosure [Line Items]
Operating loss carryforwards expiration period	2020
Latest Tax Year [Member]
Income Taxes Disclosure [Line Items]
Operating loss carryforwards expiration period	2038
Conductus [Member] | Federal [Member]
Income Taxes Disclosure [Line Items]
Net operating loss carryforwards	$ 66,900,000
Conductus [Member] | Incurred Prior to 2016 Ownership Changes [Member]
Income Taxes Disclosure [Line Items]
Net operating loss carryforwards	$ 337,000,000