Annual report pursuant to Section 13 and 15(d)

Subsequent Events - Additional Information (Detail)

v2.4.1.9
Subsequent Events - Additional Information (Detail) (USD $)
In Thousands, except Share data, unless otherwise specified
 12 Months Ended 0 Months Ended 1 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Feb. 18, 2015
Feb. 28, 2015
Subsequent Event [Line Items]          
Proceeds from issuance of common stock and warrants, net of offering expenses $ 5,520us-gaap_ProceedsFromIssuanceOfCommonStock $ 2,392us-gaap_ProceedsFromIssuanceOfCommonStock $ 21,910us-gaap_ProceedsFromIssuanceOfCommonStock    
Subsequent Event          
Subsequent Event [Line Items]          
Common stock sold, shares       8,300,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember 		 
Warrants to purchase shares of common stock       8,300,000us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember 		 
Proceeds from issuance of common stock and warrants, net of offering expenses       $ 28,200us-gaap_ProceedsFromIssuanceOfCommonStock
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember 		 
Initial exercise price of the warrants         $ 10.86thld_WarrantsInitialExercisePrice
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Maximum exercise price of warrants after adjustment date         $ 10.86thld_WarrantMaximumAdjustedExercisePrice
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Minimum exercise price of warrants after adjustment date         $ 3.62thld_WarrantMinimumAdjustedExercisePrice
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Term of warrant         5 years
Company can force exercise of warrant if 20 day VWAP price exceeds         $ 18.00thld_WarrantsTwentyDayVWAPExceeds
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember