Summary of Significant Accounting Policies - Assumptions Used to Value Options Granted (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Net Revenue Attributable To Medicaid Medicare Insurance And Self Pay As Percentage Of Net Air Medical Revenues [Line Items]
Exercise price	$ 0.01
Expected term		7 years
Dividend yield		0.00%
Employees [Member]
Schedule Of Net Revenue Attributable To Medicaid Medicare Insurance And Self Pay As Percentage Of Net Air Medical Revenues [Line Items]
Expected term	4 years 9 months		4 years 9 months
Dividend yield	0.00%	0.00%	0.00%
Minimum [Member] | Employees [Member]
Schedule Of Net Revenue Attributable To Medicaid Medicare Insurance And Self Pay As Percentage Of Net Air Medical Revenues [Line Items]
Risk free interest rate	0.85%	0.87%	0.93%
Expected term		4 years 6 months 22 days
Dividend yield	0.00%	0.00%	0.00%
Expected volatility	55.23%	76.86%	78.27%
Minimum [Member] | Non Employees [Member]
Schedule Of Net Revenue Attributable To Medicaid Medicare Insurance And Self Pay As Percentage Of Net Air Medical Revenues [Line Items]
Risk free interest rate		1.47%
Expected volatility		82.88%
Maximum [Member] | Employees [Member]
Schedule Of Net Revenue Attributable To Medicaid Medicare Insurance And Self Pay As Percentage Of Net Air Medical Revenues [Line Items]
Risk free interest rate	1.45%	1.20%	1.64%
Expected term		4 years 9 months
Dividend yield	0.00%	0.00%	0.00%
Expected volatility	79.29%	83.09%	81.36%
Maximum [Member] | Non Employees [Member]
Schedule Of Net Revenue Attributable To Medicaid Medicare Insurance And Self Pay As Percentage Of Net Air Medical Revenues [Line Items]
Risk free interest rate		1.54%
Expected volatility		83.09%
Warrant [Member]
Schedule Of Net Revenue Attributable To Medicaid Medicare Insurance And Self Pay As Percentage Of Net Air Medical Revenues [Line Items]
Stock price			$ 5.60
Exercise price			$ 12.16
Risk free interest rate			0.03%
Expected term			3 months
Dividend yield			0.00%
Expected volatility			22.76%