Income Taxes - Significant Components of our Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current Federal, State and Local, Tax Expense (Benefit) [Abstract]
Total provision for income taxes	$ 269	$ 249	$ 204
Change in tax rate	(4,058)	0	37,690
Geographic Distribution, Domestic [Member]
Current Federal, State and Local, Tax Expense (Benefit) [Abstract]
Total provision for income taxes	0	0	0
Geographic Distribution, Foreign [Member]
Current Federal, State and Local, Tax Expense (Benefit) [Abstract]
Total provision for income taxes	$ 269	$ 249	$ 204

Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, attributable to increase (decrease) in the income tax rates.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=116821951&loc=d3e32059-109318

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Name:	us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration