| Business Acquisition, Pro Forma Information, Nonrecurring Adjustments [Table Text Block] |  |  | 
The following adjustments were included in the unaudited pro forma combined net income (loss): 
|  |  
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  
|   | Three Months Ended September 30, |   | Nine Months Ended September 30, |  
|   | 2017 |   | 2016 |   | 2017 |   | 2016 |  
|   | (in thousands) |  
| Net income (loss) | $ | (9,167 | ) |   | $ | 9,679 | 
 |   | $ | 10,261 | 
 |   | $ | 52,944 | 
 |  
| Add: Results of operations – acquired business | — | 
 |   | (2,510 | ) |   | (8,916 | ) |   | (869 | ) |  
| Less: Proforma adjustments |   |   |   |   |   |   |   |  
| Depreciation of property, plant and equipment | 1,199 | 
 |   | (217 | ) |   | 970 | 
 |   | 555 | 
 |  
| Amortization of intangible assets | 1,966 | 
 |   | (10,055 | ) |   | (9,498 | ) |   | (33,717 | ) |  
| Amortization of inventory step-up | 9,715 | 
 |   | (5,051 | ) |   | 15,818 | 
 |   | (26,503 | ) |  
| Impairment of intangible assets | — | 
 |   | — | 
 |   | — | 
 |   | 1,519 | 
 |  
| Acquisition and integration expenses | 982 | 
 |   | — | 
 |   | 16,389 | 
 |   | (16,389 | ) |  
| Interest expense | 360 | 
 |   | (3,806 | ) |   | (5,029 | ) |   | (11,460 | ) |  
| Income tax benefit | (126 | ) |   | — | 
 |   | 1,760 | 
 |   | — | 
 |  
| Net income (loss) – proforma combined | $ | 4,929 | 
 |   | $ | (11,960 | ) |   | $ | 21,755 | 
 |   | $ | (33,920 | ) |  
|   |   |   |   |   |   |   |   |  
| Net income (loss) per share - proforma combined: |   |   |   |   |   |   |   |  
| Basic | $ | 0.07 | 
 |   | $ | (0.19 | ) |   | $ | 0.33 | 
 |   | $ | (0.53 | ) |  
| Diluted | $ | 0.07 | 
 |   | $ | (0.19 | ) |   | $ | 0.31 | 
 |   | $ | (0.53 | ) |  
| Shares used to compute net income (loss) per share - proforma combined |   |   |   |   |   |   |   |  
| Basic | 66,712 | 
 |   | 64,241 | 
 |   | 65,950 | 
 |   | 63,454 | 
 |  
| Diluted | 69,668 | 
 |   | 64,241 | 
 |   | 69,491 | 
 |   | 63,454 | 
 |  |  |