Business Overview - Additional Information (Detail)	6 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) Item $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of commercial products | Item		10
Number of radiopharmacies owned | Item		7
Common stock, number of shares issued and sold | shares		30,364,501	18,080,944
Proceeds from issuance of common stock in initial public offering, net of issuance costs		$ 73,539,000
Term loan facility, Face amount			$ 400,000,000
Net proceeds of the Term Facility, IPO and cash	$ 10,900,000
Common stock, stock split ratio		0.355872
Common stock, par value | $ / shares		$ 0.01	$ 0.01
Amount reclassified from other noncurrent assets to long-term debt			$ 6,400,000
Unamortized debt issuance costs		$ 5,700,000
IPO [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Common stock, number of shares issued and sold | shares	12,256,577
Proceeds from issuance of common stock in initial public offering, net of issuance costs	$ 67,200,000
Underwriting discounts, commissions and related expenses	$ 6,400,000
Over-Allotment Option [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Common stock, number of shares issued and sold | shares	1,423,243
Previously Reported [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Common stock, par value | $ / shares		$ 0.001
Common Stock [Member] | IPO [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Shares issued, price per share | $ / shares	$ 6.00
Senior Secured Term Loan Facility [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Term loan facility, Face amount	$ 365,000,000
Aggregate principal amount outstanding		$ 364,088,000
Unamortized debt issuance costs		5,684,000
Senior Notes [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Aggregate principal amount outstanding	$ 400,000,000	$ 400,000,000
Notes interest rate		9.75%
Unamortized debt issuance costs		$ 5,800,000
Senior Notes Due 2017 [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Notes interest rate	9.75%
Revolving Line of Credit [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Outstanding borrowing	$ 8,000,000	8,000,000
Borrowing base		46,200,000
Unfunded standby letter of credit outstanding		8,800,000	$ 8,800,000
Available borrowing capacity		37,300,000
Accrued interest		$ 100,000
LMI [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Outstanding borrowing	$ 50,000,000