Income Taxes - Schedule of Income tax Recovery (Detail)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Statutory federal income tax rate	(21.00%)	(21.00%)	(35.00%)
Change in tax rate	0.00%	(0.10%)	(3.60%)
State income taxes	0.00%	(1.40%)	(0.60%)
Foreign rate differential	(0.20%)	(4.30%)	7.90%
Acquired in-process research and development	14.40%	0.00%	0.00%
Stock compensation	2.60%	2.80%	2.00%
Change in valuation allowance	(0.60%)	24.80%	25.40%
Expiration of NOLs (section 382)	5.40%
Effect of the U.S. Tax Cuts and Jobs Act			4.60%
Other	(0.60%)	(0.80%)	(0.70%)
Income tax recovery	0.00%	0.00%	0.00%

Effective Income Tax Rate Reconciliation Expiration Of Net Operating Losses

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Effective income tax reconciliation effect of Tax Cuts and Jobs Act.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage 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 changes in the valuation allowance for deferred tax assets.

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Percentage 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 applicable to statutory income tax expense (benefit) outside of the country of domicile.

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Percentage 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 applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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