Income Taxes - Schedule of effective income tax rate reconciliation (Details)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Computation of Effective Income Tax Rate [Abstract]
Federal statutory tax rate	21.00%	34.00%
State taxes	4.40%	(0.90%)
Non deductible expenses	(0.60%)	19.40%
Tax credits	4.60%	(90.60%)
Expired tax credits	(3.90%)	0.00%
Stock based compensation	0.80%	(69.60%)
Foreign income tax rate differential	0.00%	(14.00%)
Repatriation Tax	0.00%	110.50%
Impact of Tax Cuts and Jobs Act enactment	0.00%	1241.00%
Valuation allowance	(167.00%)	0.00%
Tax return and audit adjustments	0.00%	(107.30%)
Contingent purchase revaluation	(1.00%)	(88.00%)
Other	(0.10%)	(1.70%)
Total	(141.80%)	1032.80%

Effective Income Tax Rate Reconciliation, Business Acquisition, Contingent Consideration, Percent

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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 attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits.

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