XML 56 R46.htm IDEA: XBRL DOCUMENT v3.19.1
Debt - Additional Information (Detail)
3 Months Ended
May 02, 2017
USD ($)
Jul. 22, 2016
USD ($)
Aug. 04, 2015
USD ($)
Mar. 31, 2019
USD ($)
d
$ / shares
shares
2015 Term Loan [Member]        
Debt Instrument [Line Items]        
Carrying value of term loan       $ 11,280,000
Liability component of Convertible Notes recorded as long-term debt       $ 12,162,000
Mid Cap Financial Trust [Member] | 2015 Term Loan [Member]        
Debt Instrument [Line Items]        
Term loan, maximum borrowings     $ 30,000,000  
Debt instrument description       The Company also agreed to maintain a balance in cash or cash equivalents at Silicon Valley Bank equal to the principal balance of the loan plus 5%.
Debt instrument percentage of cash or cash equivalents addition to principal balance     5.00%  
Debt instrument interest rate     6.25%  
Term loan, first periodic payment date     Mar. 01, 2017  
Debt instrument maturity date     Feb. 01, 2020  
Interest on final payment     9.00%  
Term loan, payment description       Interest-only period of 19 months, principal is due in 36 equal monthly installments.
Carrying value of term loan       $ 11,300,000
Debt issuance costs     $ 150,000  
Mid Cap Financial Trust [Member] | 2015 Term Loan [Member] | Interest-Only-Strip [Member]        
Debt Instrument [Line Items]        
Term loan, Interest payment period     19 months  
Mid Cap Financial Trust [Member] | 2015 Term Loan [Member] | Principal-Only-Strip [Member]        
Debt Instrument [Line Items]        
Term loan, Interest payment period     36 months  
Mid Cap Financial Trust [Member] | 2015 Term Loan [Member] | Initial Term Loan [Member]        
Debt Instrument [Line Items]        
Term loan, currently borrowed     $ 15,000,000  
Mid Cap Financial Trust [Member] | 2015 Term Loan [Member] | Second Term Loan [Member]        
Debt Instrument [Line Items]        
Term loan remaining amount borrowed   $ 15,000,000    
2024 Convertible Notes [Member]        
Debt Instrument [Line Items]        
Debt instrument interest rate 3.375%     3.375%
Debt instrument maturity date May 01, 2024      
Debt issuance costs       $ 6,470,000
Debt instrument principal amount $ 201,300,000      
Debt instrument interest rate 3.375%     9.71%
Debt instrument frequency of periodic payment       semi-annually
Net proceeds from offering of convertible senior notes $ 194,800,000      
Debt discount and issuance costs 6,500,000     $ 68,900,000
Number of shares issued upon conversion of $1,000 debt principal amount | shares       37.3413
Debt instrument convertible initial conversion price per share of common stock | $ / shares       $ 26.78
Number of days within 30 consecutive trading days in which the closing price of the entity's common stock must exceed the conversion price for the notes to be convertible into common stock | d       20
Number of consecutive trading days during which the closing price of the entity's common stock must exceed the conversion price for at least 20 days in order for the notes to be convertible into common stock | d       30
Percentage of the closing sales price of the entity's common stock that the conversion price must exceed in order for the notes to be convertible       130.00%
Number of consecutive business days immediately after any five consecutive trading day period during the note measurement period | d       5
Number of consecutive trading days before five consecutive business days during the note measurement period | d       10
Liability component of Convertible Notes recorded as long-term debt 136,700,000      
Equity component of Convertible Notes recorded as additional paid-in capital $ 64,500,000      
Debt instrument effective interest rate period       7 years
Debt issuance costs       $ 6,500,000
Debt issuance costs allocated to liability component       4,400,000
Debt issuance costs allocated to equity component reduction to additional paid-in capital       2,100,000
Interest expense       3,600,000
Amortization of debt discount       $ 1,900,000
2024 Convertible Notes [Member] | On or After February 1, 2024 [Member]        
Debt Instrument [Line Items]        
Number of days within 30 consecutive trading days in which the closing price of the entity's common stock must exceed the conversion price for the notes to be convertible into common stock | d       20
Number of consecutive trading days during which the closing price of the entity's common stock must exceed the conversion price for at least 20 days in order for the notes to be convertible into common stock | d       30
Percentage of the closing sales price of the entity's common stock that the conversion price must exceed in order for the notes to be convertible       130.00%
Debt instrument redemption date       May 06, 2020
Redemption price percentage of principal amount to be redeemed       100.00%
2024 Convertible Notes [Member] | Maximum [Member]        
Debt Instrument [Line Items]        
Debt instrument conversion obligation trading price as percentage of product common stock closing sale price and conversion rate       98.00%