XML 45 R34.htm IDEA: XBRL DOCUMENT v3.8.0.1
STOCK INCENTIVE PLANS - Summary of Stock Option Activity (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Number of Shares    
Outstanding, beginning balance (in shares) 3,099,173  
Options granted (in shares) 1,009,250  
Options exercised (in shares) (12,147)  
Options canceled (in shares) (1,136)  
Outstanding, ending balance (in shares) 4,095,140 3,099,173
Vested and expected to vest (in shares) 4,095,140  
Exercisable (in shares) 1,937,526  
Weighted Average Exercise Price    
Outstanding, beginning balance (in dollars per share) $ 7.74  
Options granted (in dollars per share) 4.29  
Options exercised (in dollars per share) 2.29  
Options canceled (in dollars per share) 11.14  
Outstanding, ending balance (in dollars per share) 6.90 $ 7.74
Vested and expected to vest (in dollars per share) 6.90  
Exercisable (in dollars per share) $ 7.42  
Weighted Average Remaining Contractual Life    
Outstanding, life 8 years 4 months 17 days 8 years 1 month 6 days
Vested and expected to vest, life 8 years 4 months 17 days  
Exercisable, life 7 years 5 months 12 days  
Total Aggregate Intrinsic Value    
Outstanding $ 837 $ 2,264
Vested and expected to vest 837  
Exercisable $ 746