Summary of Option Activity (Parenthetical) (Detail) $ in Thousands		12 Months Ended
		Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 Installment shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Underlying Outstanding Options, Options assumed in merger	[1]		94,721
Aggregate fractional shares written off in merger	[1]	4
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock awards, assumed in merger			190
Number of Shares Underlying Outstanding Options, Options assumed in merger			94,721
Number of equal annual installments | Installment			2
Aggregate fractional shares written off in merger		4
Total stock based compensation | $		$ 20

[1] In connection with the merger, the Company assumed stock options covering an aggregate of 94,721 shares of common stock. The company also assumed 190 shares of Restricted Stock Awards which vested in two equal annual installments beginning on December 31, 2015 and fully vesting on December 31, 2016 and excludes 4 aggregate fractional shares written off as a result of the conversion ratio applied to options assumed in the merger. Total stock based compensation related to these restricted stock awards was $0.02 million for year ended December 31, 2016.