Quarterly report pursuant to Section 13 or 15(d)

Percentage of Net Revenue and Total Accounts Receivable (Detail)

v3.8.0.1
Percentage of Net Revenue and Total Accounts Receivable (Detail)
 1 Months Ended 3 Months Ended
Mar. 23, 2018
 [1]
Mar. 31, 2018
Mar. 31, 2017
Sales Revenue, Net | Payor A [Member]      
Accounts Receivable And Net Revenue [Line Items]      
Concentration Risk, Percentage   12.90%
Sales Revenue, Net | Payor B [Member]      
Accounts Receivable And Net Revenue [Line Items]      
Concentration Risk, Percentage   12.00% 24.00%
Sales Revenue, Net | Payor C [Member]      
Accounts Receivable And Net Revenue [Line Items]      
Concentration Risk, Percentage   11.90%
Sales Revenue, Net | Payor D [Member]      
Accounts Receivable And Net Revenue [Line Items]      
Concentration Risk, Percentage   10.90% 12.70%
Accounts Receivable | Payor D [Member]      
Accounts Receivable And Net Revenue [Line Items]      
Concentration Risk, Percentage   25.60% 23.80%
Accounts Receivable | Payor E [Member]      
Accounts Receivable And Net Revenue [Line Items]      
Concentration Risk, Percentage   38.20% 30.50%
[1] Less than 10% of total net revenues