Annual report pursuant to Section 13 and 15(d)

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Net Loss per Share (Details)

v3.8.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Net Loss per Share (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
EPS Numerator:                      
Net loss $ (25,871) $ (17,660) $ (19,147) $ (15,314) $ (15,590) $ (22,629) $ (13,533) $ (17,464) $ (77,992) $ (69,216) $ (51,464)
EPS Denominator - Basic and Diluted:                      
Weighted average common shares outstanding 144,252 124,628 122,500 113,598 98,981 95,454 92,495 90,555 126,324 94,387 88,434
Net loss per common share:                      
Basic and diluted (in dollars per share) $ (0.18) $ (0.14) $ (0.16) $ (0.13) $ (0.16) $ (0.24) $ (0.15) $ (0.19) $ (0.62) $ (0.73) $ (0.58)
Weighted Average                      
Net loss per common share:                      
Weighted average exercise price of options (in dollars per share) $ 5.45       6.25       $ 5.45 6.25 7.08
Weighted average exercise price of warrant (in dollars per share)         $ 6.61         $ 6.61 $ 6.61
Employee stock option                      
Net loss per common share:                      
Antidilutive securities excluded from computation of earnings per share (in shares)                 20,408 20,257 19,106
Warrant to purchase common stock                      
Net loss per common share:                      
Antidilutive securities excluded from computation of earnings per share (in shares)                   32 200