Income Taxes - Summary of Provision for Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
United States federal tax statutory rate, Amount									$ (13,682)	$ (50,352)	$ (42,671)
State taxes (net of deferred benefit), Amount									(1,080)	(4,663)	(2,487)
Non-deductible expenses, Amount									(1,320)	466	667
Change in fair market value of contingent consideration, Amount									(256)	777
Warrant remeasurement and financing costs, Amount									(3,630)	(32,348)
Research & Development Credits, Amount									(803)	(712)	(922)
Change in unrecognized tax benefits, Amount									161	142	186
Foreign tax rate differential, Amount									(96)	3,619	3,969
Goodwill impairment, Amount											20,816
Change in enacted tax rates and other, net, Amount									252	35,440	(1,069)
Change in valuation allowance, Amount									9,817	(20,365)	15,988
Income tax benefit	$ (823)	$ (781)	$ (883)	$ (890)	$ (963)	$ (738)	$ (741)	$ (858)	$ (3,377)	$ (3,300)	$ (5,523)
United States federal tax statutory rate, Percent of Pretax Earnings									21.00%	34.00%	34.00%
State taxes (net of deferred benefit), Percent of Pretax Earnings									1.70%	3.10%	2.00%
Non-deductible expenses, Percent of Pretax Earnings									2.00%	(0.30%)	(0.50%)
Change in fair market value of contingent consideration, Percent of Pretax Earnings									0.40%	(0.50%)
Warrant remeasurement and financing costs, Percent of Pretax Earnings									(5.60%)	(21.80%)
Research & Development Credits, Percent of Pretax Earnings									1.20%	0.50%	0.70%
Change in unrecognized tax benefits, Percent of Pretax Earnings									(0.20%)	(0.10%)	(0.10%)
Foreign tax rate differential, Percent of Pretax Earnings									0.10%	(2.40%)	(3.20%)
Goodwill impairment, Percent of Pretax Earnings											(16.60%)
Change in enacted tax rates and other, net, Percent of Pretax Earnings									(0.30%)	(24.10%)	0.80%
Change in valuation allowance, Percent of Pretax Earnings									(15.10%)	13.80%	(12.70%)
Provision for income taxes, Percent of Pretax Earnings									5.20%	2.20%	4.40%