Accrued Expenses and Other Current Liabilities  | 
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2017  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Accrued Expenses and Other Current Liabilities | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Accrued Expenses and Other Current Liabilities | 
 8. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities are summarized as follows: 
 
  | 
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| X | ||||||||||
- Definition The entire disclosure for accounts payable and accrued liabilities at the end of the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
| X | ||||||||||
- References No definition available. 
  |